#![allow(unused, non_snake_case, dead_code, non_upper_case_globals)]
use {
    proconio::{marker::*, *},
    std::*,
    std::{cmp::*, collections::*, convert::*, iter::*, marker::*, mem::*, ops::*},
};
fn main() {
    input! {//
        n:usize,
        q:usize,
        query:[(usize,Usize1);q],
    }
    let mut ans = (n - 2).pow(2);
    let mut row = BTreeMap::new();
    let mut col = BTreeMap::new();
    row.insert(n - 1, n - 2);
    col.insert(n - 1, n - 2);
    for &(qq, x) in query.iter() {
        match qq {
            1 => {
                let a = col.range(x..).next().unwrap();
                ans -= a.1;
                let mut k = row.entry(*(a.1)).or_insert(n - 1);
                *k = min(*k, x - 1);
            }
            _ => {
                let a = row.range(x..).next().unwrap();
                ans -= a.1;
                let mut k = col.entry(*(a.1)).or_insert(n - 1);
                *k = min(*k, x - 1);
            }
        };
    }
    let mut k = ModInt1000000007::new(3);
    println!("{}", ans);
}

pub use dsu::Dsu;
pub use fenwicktree::FenwickTree;
pub use math::{crt, floor_sum, inv_mod, pow_mod};
pub use maxflow::{Edge, MfGraph};
pub use mincostflow::MinCostFlowGraph;
pub use modint::{
    Barrett, DefaultId, DynamicModInt, Id, Mod1000000007, Mod998244353, ModInt, ModInt1000000007,
    ModInt998244353, Modulus, RemEuclidU32, StaticModInt,
};
pub use scc::SccGraph;
pub use string::{
    lcp_array, lcp_array_arbitrary, suffix_array, suffix_array_arbitrary, suffix_array_manual,
    z_algorithm, z_algorithm_arbitrary,
};
pub use twosat::TwoSat;

mod convolution {}
mod dsu {
    /// Implement (union by size) + (path compression)
    /// Reference:
    /// Zvi Galil and Giuseppe F. Italiano,
    /// Data structures and algorithms for disjoint set union problems
    pub struct Dsu {
        n: usize,
        // root node: -1 * component size
        // otherwise: parent
        parent_or_size: Vec<i32>,
    }

    impl Dsu {
        // 0 <= size <= 10^8 is constrained.
        pub fn new(size: usize) -> Self {
            Self {
                n: size,
                parent_or_size: vec![-1; size],
            }
        }
        pub fn merge(&mut self, a: usize, b: usize) -> usize {
            assert!(a < self.n);
            assert!(b < self.n);
            let (mut x, mut y) = (self.leader(a), self.leader(b));
            if x == y {
                return x;
            }
            if -self.parent_or_size[x] < -self.parent_or_size[y] {
                std::mem::swap(&mut x, &mut y);
            }
            self.parent_or_size[x] += self.parent_or_size[y];
            self.parent_or_size[y] = x as i32;
            x
        }

        pub fn same(&mut self, a: usize, b: usize) -> bool {
            assert!(a < self.n);
            assert!(b < self.n);
            self.leader(a) == self.leader(b)
        }
        pub fn leader(&mut self, a: usize) -> usize {
            assert!(a < self.n);
            if self.parent_or_size[a] < 0 {
                return a;
            }
            self.parent_or_size[a] = self.leader(self.parent_or_size[a] as usize) as i32;
            self.parent_or_size[a] as usize
        }
        pub fn size(&mut self, a: usize) -> usize {
            assert!(a < self.n);
            let x = self.leader(a);
            -self.parent_or_size[x] as usize
        }
        pub fn groups(&mut self) -> Vec<Vec<usize>> {
            let mut leader_buf = vec![0; self.n];
            let mut group_size = vec![0; self.n];
            for i in 0..self.n {
                leader_buf[i] = self.leader(i);
                group_size[leader_buf[i]] += 1;
            }
            let mut result = vec![Vec::new(); self.n];
            for i in 0..self.n {
                result[i].reserve(group_size[i]);
            }
            for i in 0..self.n {
                result[leader_buf[i]].push(i);
            }
            result
                .into_iter()
                .filter(|x| !x.is_empty())
                .collect::<Vec<Vec<usize>>>()
        }
    }

    #[cfg(test)]
    mod tests {
        use super::*;

        #[test]
        fn dsu_works() {
            let mut d = Dsu::new(4);
            d.merge(0, 1);
            assert_eq!(d.same(0, 1), true);
            d.merge(1, 2);
            assert_eq!(d.same(0, 2), true);
            assert_eq!(d.size(0), 3);
            assert_eq!(d.same(0, 3), false);
            assert_eq!(d.groups(), vec![vec![0, 1, 2], vec![3]]);
        }
    }
}
mod fenwicktree {
    // Reference: https://en.wikipedia.org/wiki/Fenwick_tree
    pub struct FenwickTree<T> {
        n: usize,
        ary: Vec<T>,
        e: T,
    }

    impl<T: Clone + std::ops::AddAssign<T>> FenwickTree<T> {
        pub fn new(n: usize, e: T) -> Self {
            FenwickTree {
                n,
                ary: vec![e.clone(); n],
                e,
            }
        }
        pub fn accum(&self, mut idx: usize) -> T {
            let mut sum = self.e.clone();
            while idx > 0 {
                sum += self.ary[idx - 1].clone();
                idx &= idx - 1;
            }
            sum
        }
        /// performs data[idx] += val;
        pub fn add<U: Clone>(&mut self, mut idx: usize, val: U)
        where
            T: std::ops::AddAssign<U>,
        {
            let n = self.n;
            idx += 1;
            while idx <= n {
                self.ary[idx - 1] += val.clone();
                idx += idx & idx.wrapping_neg();
            }
        }
        /// Returns data[l] + ... + data[r - 1].
        pub fn sum(&self, l: usize, r: usize) -> T
        where
            T: std::ops::Sub<Output = T>,
        {
            self.accum(r) - self.accum(l)
        }
    }

    #[cfg(test)]
    mod tests {
        use super::*;

        #[test]
        fn fenwick_tree_works() {
            let mut bit = FenwickTree::new(5, 0i64);
            // [1, 2, 3, 4, 5]
            for i in 0..5 {
                bit.add(i, i as i64 + 1);
            }
            assert_eq!(bit.sum(0, 5), 15);
            assert_eq!(bit.sum(0, 4), 10);
            assert_eq!(bit.sum(1, 3), 5);
        }
    }
}
mod lazysegtree {}
mod math {
    use crate::internal_math;

    use std::mem::swap;

    #[allow(clippy::many_single_char_names)]
    pub fn pow_mod(x: i64, mut n: i64, m: u32) -> u32 {
        assert!(0 <= n && 1 <= m && m <= 2u32.pow(31));
        if m == 1 {
            return 0;
        }
        let bt = internal_math::Barrett::new(m);
        let mut r = 1;
        let mut y = internal_math::safe_mod(x, m as i64) as u32;
        while n != 0 {
            if n & 1 != 0 {
                r = bt.mul(r, y);
            }
            y = bt.mul(y, y);
            n >>= 1;
        }
        r
    }

    pub fn inv_mod(x: i64, m: i64) -> i64 {
        assert!(1 <= m);
        let z = internal_math::inv_gcd(x, m);
        assert!(z.0 == 1);
        z.1
    }

    pub fn crt(r: &[i64], m: &[i64]) -> (i64, i64) {
        assert_eq!(r.len(), m.len());
        // Contracts: 0 <= r0 < m0
        let (mut r0, mut m0) = (0, 1);
        for (&(mut ri), &(mut mi)) in r.iter().zip(m.iter()) {
            assert!(1 < mi);
            ri = internal_math::safe_mod(ri, mi);
            if m0 < mi {
                swap(&mut r0, &mut ri);
                swap(&mut m0, &mut mi);
            }
            if m0 % mi == 0 {
                if r0 % mi != ri {
                    return (0, 0);
                }
                continue;
            }
            // assume: m0 > mi, lcm(m0, mi) >= 2 * max(m0, mi)

            // (r0, m0), (ri, mi) -> (r2, m2 = lcm(m0, m1));
            // r2 % m0 = r0
            // r2 % mi = ri
            // -> (r0 + x*m0) % mi = ri
            // -> x*u0*g % (u1*g) = (ri - r0) (u0*g = m0, u1*g = mi)
            // -> x = (ri - r0) / g * inv(u0) (mod u1)

            // im = inv(u0) (mod u1) (0 <= im < u1)
            let (g, im) = internal_math::inv_gcd(m0, mi);
            let u1 = mi / g;
            // |ri - r0| < (m0 + mi) <= lcm(m0, mi)
            if (ri - r0) % g != 0 {
                return (0, 0);
            }
            // u1 * u1 <= mi * mi / g / g <= m0 * mi / g = lcm(m0, mi)
            let x = (ri - r0) / g % u1 * im % u1;

            // |r0| + |m0 * x|
            // < m0 + m0 * (u1 - 1)
            // = m0 + m0 * mi / g - m0
            // = lcm(m0, mi)
            r0 += x * m0;
            m0 *= u1; // -> lcm(m0, mi)
            if r0 < 0 {
                r0 += m0
            };
        }

        (r0, m0)
    }

    pub fn floor_sum(n: i64, m: i64, mut a: i64, mut b: i64) -> i64 {
        let mut ans = 0;
        if a >= m {
            ans += (n - 1) * n * (a / m) / 2;
            a %= m;
        }
        if b >= m {
            ans += n * (b / m);
            b %= m;
        }

        let y_max = (a * n + b) / m;
        let x_max = y_max * m - b;
        if y_max == 0 {
            return ans;
        }
        ans += (n - (x_max + a - 1) / a) * y_max;
        ans += floor_sum(y_max, a, m, (a - x_max % a) % a);
        ans
    }

    #[cfg(test)]
    mod tests {
        #![allow(clippy::unreadable_literal)]
        #![allow(clippy::cognitive_complexity)]
        use super::*;
        #[test]
        fn test_pow_mod() {
            assert_eq!(pow_mod(0, 0, 1), 0);
            assert_eq!(pow_mod(0, 0, 3), 1);
            assert_eq!(pow_mod(0, 0, 723), 1);
            assert_eq!(pow_mod(0, 0, 998244353), 1);
            assert_eq!(pow_mod(0, 0, 2u32.pow(31)), 1);

            assert_eq!(pow_mod(0, 1, 1), 0);
            assert_eq!(pow_mod(0, 1, 3), 0);
            assert_eq!(pow_mod(0, 1, 723), 0);
            assert_eq!(pow_mod(0, 1, 998244353), 0);
            assert_eq!(pow_mod(0, 1, 2u32.pow(31)), 0);

            assert_eq!(pow_mod(0, i64::max_value(), 1), 0);
            assert_eq!(pow_mod(0, i64::max_value(), 3), 0);
            assert_eq!(pow_mod(0, i64::max_value(), 723), 0);
            assert_eq!(pow_mod(0, i64::max_value(), 998244353), 0);
            assert_eq!(pow_mod(0, i64::max_value(), 2u32.pow(31)), 0);

            assert_eq!(pow_mod(1, 0, 1), 0);
            assert_eq!(pow_mod(1, 0, 3), 1);
            assert_eq!(pow_mod(1, 0, 723), 1);
            assert_eq!(pow_mod(1, 0, 998244353), 1);
            assert_eq!(pow_mod(1, 0, 2u32.pow(31)), 1);

            assert_eq!(pow_mod(1, 1, 1), 0);
            assert_eq!(pow_mod(1, 1, 3), 1);
            assert_eq!(pow_mod(1, 1, 723), 1);
            assert_eq!(pow_mod(1, 1, 998244353), 1);
            assert_eq!(pow_mod(1, 1, 2u32.pow(31)), 1);

            assert_eq!(pow_mod(1, i64::max_value(), 1), 0);
            assert_eq!(pow_mod(1, i64::max_value(), 3), 1);
            assert_eq!(pow_mod(1, i64::max_value(), 723), 1);
            assert_eq!(pow_mod(1, i64::max_value(), 998244353), 1);
            assert_eq!(pow_mod(1, i64::max_value(), 2u32.pow(31)), 1);

            assert_eq!(pow_mod(i64::max_value(), 0, 1), 0);
            assert_eq!(pow_mod(i64::max_value(), 0, 3), 1);
            assert_eq!(pow_mod(i64::max_value(), 0, 723), 1);
            assert_eq!(pow_mod(i64::max_value(), 0, 998244353), 1);
            assert_eq!(pow_mod(i64::max_value(), 0, 2u32.pow(31)), 1);

            assert_eq!(pow_mod(i64::max_value(), i64::max_value(), 1), 0);
            assert_eq!(pow_mod(i64::max_value(), i64::max_value(), 3), 1);
            assert_eq!(pow_mod(i64::max_value(), i64::max_value(), 723), 640);
            assert_eq!(
                pow_mod(i64::max_value(), i64::max_value(), 998244353),
                683296792
            );
            assert_eq!(
                pow_mod(i64::max_value(), i64::max_value(), 2u32.pow(31)),
                2147483647
            );

            assert_eq!(pow_mod(2, 3, 1_000_000_007), 8);
            assert_eq!(pow_mod(5, 7, 1_000_000_007), 78125);
            assert_eq!(pow_mod(123, 456, 1_000_000_007), 565291922);
        }

        #[test]
        #[should_panic]
        fn test_inv_mod_1() {
            inv_mod(271828, 0);
        }

        #[test]
        #[should_panic]
        fn test_inv_mod_2() {
            inv_mod(3141592, 1000000008);
        }

        #[test]
        fn test_crt() {
            let a = [44, 23, 13];
            let b = [13, 50, 22];
            assert_eq!(crt(&a, &b), (1773, 7150));
            let a = [12345, 67890, 99999];
            let b = [13, 444321, 95318];
            assert_eq!(crt(&a, &b), (103333581255, 550573258014));
        }

        #[test]
        fn test_floor_sum() {
            assert_eq!(floor_sum(0, 1, 0, 0), 0);
            assert_eq!(floor_sum(1_000_000_000, 1, 1, 1), 500_000_000_500_000_000);
            assert_eq!(
                floor_sum(1_000_000_000, 1_000_000_000, 999_999_999, 999_999_999),
                499_999_999_500_000_000
            );
            assert_eq!(floor_sum(332955, 5590132, 2231, 999423), 22014575);
        }
    }
}
mod maxflow {
    #![allow(dead_code)]
    use crate::internal_queue::SimpleQueue;
    use crate::internal_type_traits::Integral;
    use std::cmp::min;
    use std::iter;

    impl<Cap> MfGraph<Cap>
    where
        Cap: Integral,
    {
        pub fn new(n: usize) -> MfGraph<Cap> {
            MfGraph {
                _n: n,
                pos: Vec::new(),
                g: iter::repeat_with(Vec::new).take(n).collect(),
            }
        }

        pub fn add_edge(&mut self, from: usize, to: usize, cap: Cap) -> usize {
            assert!(from < self._n);
            assert!(to < self._n);
            assert!(Cap::zero() <= cap);
            let m = self.pos.len();
            self.pos.push((from, self.g[from].len()));
            let rev = self.g[to].len() + if from == to { 1 } else { 0 };
            self.g[from].push(_Edge { to, rev, cap });
            let rev = self.g[from].len() - 1;
            self.g[to].push(_Edge {
                to: from,
                rev,
                cap: Cap::zero(),
            });
            m
        }
    }

    #[derive(Debug, PartialEq, Eq)]
    pub struct Edge<Cap: Integral> {
        pub from: usize,
        pub to: usize,
        pub cap: Cap,
        pub flow: Cap,
    }

    impl<Cap> MfGraph<Cap>
    where
        Cap: Integral,
    {
        pub fn get_edge(&self, i: usize) -> Edge<Cap> {
            let m = self.pos.len();
            assert!(i < m);
            let _e = &self.g[self.pos[i].0][self.pos[i].1];
            let _re = &self.g[_e.to][_e.rev];
            Edge {
                from: self.pos[i].0,
                to: _e.to,
                cap: _e.cap + _re.cap,
                flow: _re.cap,
            }
        }
        pub fn edges(&self) -> Vec<Edge<Cap>> {
            let m = self.pos.len();
            (0..m).map(|i| self.get_edge(i)).collect()
        }
        pub fn change_edge(&mut self, i: usize, new_cap: Cap, new_flow: Cap) {
            let m = self.pos.len();
            assert!(i < m);
            assert!(Cap::zero() <= new_flow && new_flow <= new_cap);
            let (to, rev) = {
                let _e = &mut self.g[self.pos[i].0][self.pos[i].1];
                _e.cap = new_cap - new_flow;
                (_e.to, _e.rev)
            };
            let _re = &mut self.g[to][rev];
            _re.cap = new_flow;
        }

        /// `s != t` must hold, otherwise it panics.
        pub fn flow(&mut self, s: usize, t: usize) -> Cap {
            self.flow_with_capacity(s, t, Cap::max_value())
        }
        /// # Parameters
        /// * `s != t` must hold, otherwise it panics.
        /// * `flow_limit >= 0`
        pub fn flow_with_capacity(&mut self, s: usize, t: usize, flow_limit: Cap) -> Cap {
            let n_ = self._n;
            assert!(s < n_);
            assert!(t < n_);
            // By the definition of max flow in appendix.html, this function should return 0
            // when the same vertices are provided.  On the other hand, it is reasonable to
            // return infinity-like value too, which is what the original implementation
            // (and this implementation without the following assertion) does.
            // Since either return value is confusing, we'd rather deny the parameters
            // of the two same vertices.
            // For more details, see https://github.com/rust-lang-ja/ac-library-rs/pull/24#discussion_r485343451
            // and https://github.com/atcoder/ac-library/issues/5 .
            assert_ne!(s, t);
            // Additional constraint
            assert!(Cap::zero() <= flow_limit);

            let mut calc = FlowCalculator {
                graph: self,
                s,
                t,
                flow_limit,
                level: vec![0; n_],
                iter: vec![0; n_],
                que: SimpleQueue::default(),
            };

            let mut flow = Cap::zero();
            while flow < flow_limit {
                calc.bfs();
                if calc.level[t] == -1 {
                    break;
                }
                calc.iter.iter_mut().for_each(|e| *e = 0);
                while flow < flow_limit {
                    let f = calc.dfs(t, flow_limit - flow);
                    if f == Cap::zero() {
                        break;
                    }
                    flow += f;
                }
            }
            flow
        }

        pub fn min_cut(&self, s: usize) -> Vec<bool> {
            let mut visited = vec![false; self._n];
            let mut que = SimpleQueue::default();
            que.push(s);
            while !que.empty() {
                let &p = que.front().unwrap();
                que.pop();
                visited[p] = true;
                for e in &self.g[p] {
                    if e.cap != Cap::zero() && !visited[e.to] {
                        visited[e.to] = true;
                        que.push(e.to);
                    }
                }
            }
            visited
        }
    }

    struct FlowCalculator<'a, Cap> {
        graph: &'a mut MfGraph<Cap>,
        s: usize,
        t: usize,
        flow_limit: Cap,
        level: Vec<i32>,
        iter: Vec<usize>,
        que: SimpleQueue<usize>,
    }

    impl<Cap> FlowCalculator<'_, Cap>
    where
        Cap: Integral,
    {
        fn bfs(&mut self) {
            self.level.iter_mut().for_each(|e| *e = -1);
            self.level[self.s] = 0;
            self.que.clear();
            self.que.push(self.s);
            while !self.que.empty() {
                let v = *self.que.front().unwrap();
                self.que.pop();
                for e in &self.graph.g[v] {
                    if e.cap == Cap::zero() || self.level[e.to] >= 0 {
                        continue;
                    }
                    self.level[e.to] = self.level[v] + 1;
                    if e.to == self.t {
                        return;
                    }
                    self.que.push(e.to);
                }
            }
        }
        fn dfs(&mut self, v: usize, up: Cap) -> Cap {
            if v == self.s {
                return up;
            }
            let mut res = Cap::zero();
            let level_v = self.level[v];
            for i in self.iter[v]..self.graph.g[v].len() {
                self.iter[v] = i;
                let &_Edge {
                    to: e_to,
                    rev: e_rev,
                    ..
                } = &self.graph.g[v][i];
                if level_v <= self.level[e_to] || self.graph.g[e_to][e_rev].cap == Cap::zero() {
                    continue;
                }
                let d = self.dfs(e_to, min(up - res, self.graph.g[e_to][e_rev].cap));
                if d <= Cap::zero() {
                    continue;
                }
                self.graph.g[v][i].cap += d;
                self.graph.g[e_to][e_rev].cap -= d;
                res += d;
                if res == up {
                    break;
                }
            }
            self.iter[v] = self.graph.g[v].len();
            res
        }
    }

    #[derive(Default)]
    pub struct MfGraph<Cap> {
        _n: usize,
        pos: Vec<(usize, usize)>,
        g: Vec<Vec<_Edge<Cap>>>,
    }

    struct _Edge<Cap> {
        to: usize,
        rev: usize,
        cap: Cap,
    }

    #[cfg(test)]
    mod test {
        use crate::{Edge, MfGraph};

        #[test]
        fn test_max_flow_wikipedia() {
            // From https://commons.wikimedia.org/wiki/File:Min_cut.png
            // Under CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0/deed.en
            let mut graph = MfGraph::new(6);
            assert_eq!(graph.add_edge(0, 1, 3), 0);
            assert_eq!(graph.add_edge(0, 2, 3), 1);
            assert_eq!(graph.add_edge(1, 2, 2), 2);
            assert_eq!(graph.add_edge(1, 3, 3), 3);
            assert_eq!(graph.add_edge(2, 4, 2), 4);
            assert_eq!(graph.add_edge(3, 4, 4), 5);
            assert_eq!(graph.add_edge(3, 5, 2), 6);
            assert_eq!(graph.add_edge(4, 5, 3), 7);

            assert_eq!(graph.flow(0, 5), 5);

            let edges = graph.edges();
            {
                #[rustfmt::skip]
                assert_eq!(
                    edges,
                    vec![
                        Edge { from: 0, to: 1, cap: 3, flow: 3 },
                        Edge { from: 0, to: 2, cap: 3, flow: 2 },
                        Edge { from: 1, to: 2, cap: 2, flow: 0 },
                        Edge { from: 1, to: 3, cap: 3, flow: 3 },
                        Edge { from: 2, to: 4, cap: 2, flow: 2 },
                        Edge { from: 3, to: 4, cap: 4, flow: 1 },
                        Edge { from: 3, to: 5, cap: 2, flow: 2 },
                        Edge { from: 4, to: 5, cap: 3, flow: 3 },
                    ]
                );
            }
            assert_eq!(
                graph.min_cut(0),
                vec![true, false, true, false, false, false]
            );
        }

        #[test]
        fn test_max_flow_wikipedia_multiple_edges() {
            // From https://commons.wikimedia.org/wiki/File:Min_cut.png
            // Under CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0/deed.en
            let mut graph = MfGraph::new(6);
            for &(u, v, c) in &[
                (0, 1, 3),
                (0, 2, 3),
                (1, 2, 2),
                (1, 3, 3),
                (2, 4, 2),
                (3, 4, 4),
                (3, 5, 2),
                (4, 5, 3),
            ] {
                for _ in 0..c {
                    graph.add_edge(u, v, 1);
                }
            }

            assert_eq!(graph.flow(0, 5), 5);
            assert_eq!(
                graph.min_cut(0),
                vec![true, false, true, false, false, false]
            );
        }

        #[test]
        #[allow(clippy::many_single_char_names)]
        fn test_max_flow_misawa() {
            // Originally by @MiSawa
            // From https://gist.github.com/MiSawa/47b1d99c372daffb6891662db1a2b686
            let n = 100;

            let mut graph = MfGraph::new((n + 1) * 2 + 5);
            let (s, a, b, c, t) = (0, 1, 2, 3, 4);
            graph.add_edge(s, a, 1);
            graph.add_edge(s, b, 2);
            graph.add_edge(b, a, 2);
            graph.add_edge(c, t, 2);
            for i in 0..n {
                let i = 2 * i + 5;
                for j in 0..2 {
                    for k in 2..4 {
                        graph.add_edge(i + j, i + k, 3);
                    }
                }
            }
            for j in 0..2 {
                graph.add_edge(a, 5 + j, 3);
                graph.add_edge(2 * n + 5 + j, c, 3);
            }

            assert_eq!(graph.flow(s, t), 2);
        }
    }
}
mod mincostflow {
    use crate::internal_type_traits::Integral;

    pub struct MinCostFlowEdge<T> {
        pub from: usize,
        pub to: usize,
        pub cap: T,
        pub flow: T,
        pub cost: T,
    }

    pub struct MinCostFlowGraph<T> {
        pos: Vec<(usize, usize)>,
        g: Vec<Vec<_Edge<T>>>,
        cost_sum: T,
    }

    impl<T> MinCostFlowGraph<T>
    where
        T: Integral + std::ops::Neg<Output = T>,
    {
        pub fn new(n: usize) -> Self {
            Self {
                pos: vec![],
                g: (0..n).map(|_| vec![]).collect(),
                cost_sum: T::zero(),
            }
        }

        pub fn get_edge(&self, i: usize) -> MinCostFlowEdge<T> {
            assert!(i < self.pos.len());
            let e = &self.g[self.pos[i].0][self.pos[i].1];
            let re = &self.g[e.to][e.rev];
            MinCostFlowEdge {
                from: self.pos[i].0,
                to: e.to,
                cap: e.cap + re.cap,
                flow: re.cap,
                cost: e.cost,
            }
        }

        pub fn edges(&self) -> Vec<MinCostFlowEdge<T>> {
            let m = self.pos.len();
            let mut result = vec![];
            for i in 0..m {
                result.push(self.get_edge(i));
            }
            result
        }

        pub fn add_edge(&mut self, from: usize, to: usize, cap: T, cost: T) -> usize {
            assert!(from < self.g.len());
            assert!(to < self.g.len());
            assert_ne!(from, to);
            assert!(cap >= T::zero());
            assert!(cost >= T::zero());

            self.pos.push((from, self.g[from].len()));
            self.cost_sum += cost;

            let rev = self.g[to].len();
            self.g[from].push(_Edge { to, rev, cap, cost });

            let rev = self.g[from].len() - 1;
            self.g[to].push(_Edge {
                to: from,
                rev,
                cap: T::zero(),
                cost: -cost,
            });

            self.pos.len() - 1
        }

        /// Returns (maximum flow, cost)
        pub fn flow(&mut self, source: usize, sink: usize, flow_limit: T) -> (T, T) {
            self.slope(source, sink, flow_limit).pop().unwrap()
        }

        pub fn slope(&mut self, source: usize, sink: usize, flow_limit: T) -> Vec<(T, T)> {
            let n = self.g.len();
            assert!(source < n);
            assert!(sink < n);
            assert_ne!(source, sink);

            let mut dual = vec![T::zero(); n];
            let mut prev_v = vec![0; n];
            let mut prev_e = vec![0; n];
            let mut flow = T::zero();
            let mut cost = T::zero();
            let mut prev_cost: Option<T> = None;
            let mut result = vec![(flow, cost)];
            while flow < flow_limit {
                if !self.refine_dual(source, sink, &mut dual, &mut prev_v, &mut prev_e) {
                    break;
                }

                let mut c = flow_limit - flow;
                let mut v = sink;
                while v != source {
                    c = std::cmp::min(c, self.g[prev_v[v]][prev_e[v]].cap);
                    v = prev_v[v];
                }

                let mut v = sink;
                while v != source {
                    self.g[prev_v[v]][prev_e[v]].cap -= c;
                    let rev = self.g[prev_v[v]][prev_e[v]].rev;
                    self.g[v][rev].cap += c;
                    v = prev_v[v];
                }

                let d = -dual[source];
                flow += c;
                cost += d * c;
                if prev_cost == Some(d) {
                    assert!(result.pop().is_some());
                }
                result.push((flow, cost));
                prev_cost = Some(cost);
            }
            result
        }

        fn refine_dual(
            &self,
            source: usize,
            sink: usize,
            dual: &mut [T],
            pv: &mut [usize],
            pe: &mut [usize],
        ) -> bool {
            let n = self.g.len();
            let mut dist = vec![self.cost_sum; n];
            let mut vis = vec![false; n];

            let mut que = std::collections::BinaryHeap::new();
            dist[source] = T::zero();
            que.push((std::cmp::Reverse(T::zero()), source));
            while let Some((_, v)) = que.pop() {
                if vis[v] {
                    continue;
                }
                vis[v] = true;
                if v == sink {
                    break;
                }

                for (i, e) in self.g[v].iter().enumerate() {
                    if vis[e.to] || e.cap == T::zero() {
                        continue;
                    }

                    let cost = e.cost - dual[e.to] + dual[v];
                    if dist[e.to] - dist[v] > cost {
                        dist[e.to] = dist[v] + cost;
                        pv[e.to] = v;
                        pe[e.to] = i;
                        que.push((std::cmp::Reverse(dist[e.to]), e.to));
                    }
                }
            }

            if !vis[sink] {
                return false;
            }

            for v in 0..n {
                if !vis[v] {
                    continue;
                }
                dual[v] -= dist[sink] - dist[v];
            }
            true
        }
    }

    struct _Edge<T> {
        to: usize,
        rev: usize,
        cap: T,
        cost: T,
    }

    #[cfg(test)]
    mod tests {
        use super::*;

        #[test]
        fn test_min_cost_flow() {
            let mut graph = MinCostFlowGraph::new(4);
            graph.add_edge(0, 1, 2, 1);
            graph.add_edge(0, 2, 1, 2);
            graph.add_edge(1, 2, 1, 1);
            graph.add_edge(1, 3, 1, 3);
            graph.add_edge(2, 3, 2, 1);
            let (flow, cost) = graph.flow(0, 3, 2);
            assert_eq!(flow, 2);
            assert_eq!(cost, 6);
        }
    }
}
mod modint {
    //! Structs that treat the modular arithmetic.
    //!
    //! # Major changes from the original ACL
    //!
    //! - Converted the struct names to PascalCase.
    //! - Renamed `mod` → `modulus`.
    //! - Moduli are `u32`, not `i32`.
    //! - `Id`s are `usize`, not `i32`.
    //! - The default `Id` is `0`, not `-1`.
    //! - The type of the argument of `pow` is `u64`, not `i64`.
    //! - Modints implement `FromStr` and `Display`. Modints in the original ACL don't have `operator<<` or `operator>>`.

    use crate::internal_math;
    use std::{
        cell::RefCell,
        convert::{Infallible, TryInto as _},
        fmt,
        hash::{Hash, Hasher},
        iter::{Product, Sum},
        marker::PhantomData,
        ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub, SubAssign},
        str::FromStr,
        thread::LocalKey,
    };

    pub type ModInt1000000007 = StaticModInt<Mod1000000007>;
    pub type ModInt998244353 = StaticModInt<Mod998244353>;
    pub type ModInt = DynamicModInt<DefaultId>;

    /// Corresponds to `atcoder::static_modint` in the original ACL.
    #[derive(Copy, Clone, Eq, PartialEq)]
    #[repr(transparent)]
    pub struct StaticModInt<M> {
        val: u32,
        phantom: PhantomData<fn() -> M>,
    }

    impl<M: Modulus> StaticModInt<M> {
        /// Corresponds to `atcoder::static_modint::mod` in the original ACL.
        #[inline(always)]
        pub fn modulus() -> u32 {
            M::VALUE
        }

        /// Creates a new `StaticModInt`.
        #[inline]
        pub fn new<T: RemEuclidU32>(val: T) -> Self {
            Self::raw(val.rem_euclid_u32(M::VALUE))
        }

        /// Corresponds to `atcoder::static_modint::raw` in the original ACL.
        #[inline]
        pub fn raw(val: u32) -> Self {
            Self {
                val,
                phantom: PhantomData,
            }
        }

        /// Corresponds to `atcoder::static_modint::val` in the original ACL.
        #[inline]
        pub fn val(self) -> u32 {
            self.val
        }

        /// Corresponds to `atcoder::static_modint::pow` in the original ACL.
        #[inline]
        pub fn pow(self, n: u64) -> Self {
            <Self as ModIntBase>::pow(self, n)
        }

        /// Corresponds to `atcoder::static_modint::inv` in the original ACL.
        ///
        /// # Panics
        ///
        /// Panics if the multiplicative inverse does not exist.
        #[inline]
        pub fn inv(self) -> Self {
            if M::HINT_VALUE_IS_PRIME {
                if self.val() == 0 {
                    panic!("attempt to divide by zero");
                }
                debug_assert!(
                    internal_math::is_prime(M::VALUE.try_into().unwrap()),
                    "{} is not a prime number",
                    M::VALUE,
                );
                self.pow((M::VALUE - 2).into())
            } else {
                Self::inv_for_non_prime_modulus(self)
            }
        }
    }

    impl<M: Modulus> ModIntBase for StaticModInt<M> {
        #[inline(always)]
        fn modulus() -> u32 {
            Self::modulus()
        }

        #[inline]
        fn raw(val: u32) -> Self {
            Self::raw(val)
        }

        #[inline]
        fn val(self) -> u32 {
            self.val()
        }

        #[inline]
        fn inv(self) -> Self {
            self.inv()
        }
    }

    pub trait Modulus: 'static + Copy + Eq {
        const VALUE: u32;
        const HINT_VALUE_IS_PRIME: bool;
        // does not work well
        //const _STATIC_ASSERT_VALUE_IS_NON_ZERO: () = [()][(Self::VALUE == 0) as usize];
    }

    #[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Debug)]
    pub enum Mod1000000007 {}

    impl Modulus for Mod1000000007 {
        const VALUE: u32 = 1_000_000_007;
        const HINT_VALUE_IS_PRIME: bool = true;
    }

    #[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Debug)]
    pub enum Mod998244353 {}

    impl Modulus for Mod998244353 {
        const VALUE: u32 = 998_244_353;
        const HINT_VALUE_IS_PRIME: bool = true;
    }

    #[derive(Copy, Clone, Eq, PartialEq)]
    #[repr(transparent)]
    pub struct DynamicModInt<I> {
        val: u32,
        phantom: PhantomData<fn() -> I>,
    }

    impl<I: Id> DynamicModInt<I> {
        #[inline]
        pub fn modulus() -> u32 {
            I::companion_barrett().with(|bt| bt.borrow().umod())
        }

        #[inline]
        pub fn set_modulus(modulus: u32) {
            if modulus == 0 {
                panic!("the modulus must not be 0");
            }
            I::companion_barrett().with(|bt| *bt.borrow_mut() = Barrett::new(modulus))
        }

        #[inline]
        pub fn new<T: RemEuclidU32>(val: T) -> Self {
            <Self as ModIntBase>::new(val)
        }

        #[inline]
        pub fn raw(val: u32) -> Self {
            Self {
                val,
                phantom: PhantomData,
            }
        }

        #[inline]
        pub fn val(self) -> u32 {
            self.val
        }

        #[inline]
        pub fn pow(self, n: u64) -> Self {
            <Self as ModIntBase>::pow(self, n)
        }

        #[inline]
        pub fn inv(self) -> Self {
            Self::inv_for_non_prime_modulus(self)
        }
    }

    impl<I: Id> ModIntBase for DynamicModInt<I> {
        #[inline]
        fn modulus() -> u32 {
            Self::modulus()
        }

        #[inline]
        fn raw(val: u32) -> Self {
            Self::raw(val)
        }

        #[inline]
        fn val(self) -> u32 {
            self.val()
        }

        #[inline]
        fn inv(self) -> Self {
            self.inv()
        }
    }

    pub trait Id: 'static + Copy + Eq {
        // TODO: Make `internal_math::Barret` `Copy`.
        fn companion_barrett() -> &'static LocalKey<RefCell<Barrett>>;
    }

    #[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Debug)]
    pub enum DefaultId {}

    impl Id for DefaultId {
        fn companion_barrett() -> &'static LocalKey<RefCell<Barrett>> {
            thread_local! {
                static BARRETT: RefCell<Barrett> = RefCell::default();
            }
            &BARRETT
        }
    }

    pub struct Barrett(internal_math::Barrett);

    impl Barrett {
        #[inline]
        pub fn new(m: u32) -> Self {
            Self(internal_math::Barrett::new(m))
        }

        #[inline]
        fn umod(&self) -> u32 {
            self.0.umod()
        }

        #[inline]
        fn mul(&self, a: u32, b: u32) -> u32 {
            self.0.mul(a, b)
        }
    }

    impl Default for Barrett {
        #[inline]
        fn default() -> Self {
            Self(internal_math::Barrett::new(998_244_353))
        }
    }

    pub trait ModIntBase:
        Default
        + FromStr
        + From<i8>
        + From<i16>
        + From<i32>
        + From<i64>
        + From<i128>
        + From<u8>
        + From<u16>
        + From<u32>
        + From<u64>
        + From<u128>
        + Copy
        + Eq
        + Hash
        + fmt::Display
        + fmt::Debug
        + Neg<Output = Self>
        + Add<Output = Self>
        + Sub<Output = Self>
        + Mul<Output = Self>
        + Div<Output = Self>
        + AddAssign
        + SubAssign
        + MulAssign
        + DivAssign
    {
        fn modulus() -> u32;
        fn raw(val: u32) -> Self;
        fn val(self) -> u32;
        fn inv(self) -> Self;

        #[inline]
        fn new<T: RemEuclidU32>(val: T) -> Self {
            Self::raw(val.rem_euclid_u32(Self::modulus()))
        }

        #[inline]
        fn pow(self, mut n: u64) -> Self {
            let mut x = self;
            let mut r = Self::raw(1);
            while n > 0 {
                if n & 1 == 1 {
                    r *= x;
                }
                x *= x;
                n >>= 1;
            }
            r
        }
    }

    pub trait RemEuclidU32 {
        fn rem_euclid_u32(self, modulus: u32) -> u32;
    }

    macro_rules! impl_rem_euclid_u32_for_small_signed {
        ($($ty:tt),*) => {
            $(
                impl RemEuclidU32 for $ty {
                    #[inline]
                    fn rem_euclid_u32(self, modulus: u32) -> u32 {
                        (self as i64).rem_euclid(i64::from(modulus)) as _
                    }
                }
            )*
        }
    }

    impl_rem_euclid_u32_for_small_signed!(i8, i16, i32, i64, isize);

    impl RemEuclidU32 for i128 {
        #[inline]
        fn rem_euclid_u32(self, modulus: u32) -> u32 {
            self.rem_euclid(i128::from(modulus)) as _
        }
    }

    macro_rules! impl_rem_euclid_u32_for_small_unsigned {
        ($($ty:tt),*) => {
            $(
                impl RemEuclidU32 for $ty {
                    #[inline]
                    fn rem_euclid_u32(self, modulus: u32) -> u32 {
                        self as u32 % modulus
                    }
                }
            )*
        }
    }

    macro_rules! impl_rem_euclid_u32_for_large_unsigned {
        ($($ty:tt),*) => {
            $(
                impl RemEuclidU32 for $ty {
                    #[inline]
                    fn rem_euclid_u32(self, modulus: u32) -> u32 {
                        (self % (modulus as $ty)) as _
                    }
                }
            )*
        }
    }

    impl_rem_euclid_u32_for_small_unsigned!(u8, u16, u32);
    impl_rem_euclid_u32_for_large_unsigned!(u64, u128);

    #[cfg(target_pointer_width = "32")]
    impl_rem_euclid_u32_for_small_unsigned!(usize);

    #[cfg(target_pointer_width = "64")]
    impl_rem_euclid_u32_for_large_unsigned!(usize);

    trait InternalImplementations: ModIntBase {
        #[inline]
        fn inv_for_non_prime_modulus(this: Self) -> Self {
            let (gcd, x) = internal_math::inv_gcd(this.val().into(), Self::modulus().into());
            if gcd != 1 {
                panic!("the multiplicative inverse does not exist");
            }
            Self::new(x)
        }

        #[inline]
        fn default_impl() -> Self {
            Self::raw(0)
        }

        #[inline]
        fn from_str_impl(s: &str) -> Result<Self, Infallible> {
            Ok(s.parse::<i64>()
                .map(Self::new)
                .unwrap_or_else(|_| todo!("parsing as an arbitrary precision integer?")))
        }

        #[inline]
        fn hash_impl(this: &Self, state: &mut impl Hasher) {
            this.val().hash(state)
        }

        #[inline]
        fn display_impl(this: &Self, f: &mut fmt::Formatter) -> fmt::Result {
            fmt::Display::fmt(&this.val(), f)
        }

        #[inline]
        fn debug_impl(this: &Self, f: &mut fmt::Formatter) -> fmt::Result {
            fmt::Debug::fmt(&this.val(), f)
        }

        #[inline]
        fn neg_impl(this: Self) -> Self {
            Self::sub_impl(Self::raw(0), this)
        }

        #[inline]
        fn add_impl(lhs: Self, rhs: Self) -> Self {
            let modulus = Self::modulus();
            let mut val = lhs.val() + rhs.val();
            if val >= modulus {
                val -= modulus;
            }
            Self::raw(val)
        }

        #[inline]
        fn sub_impl(lhs: Self, rhs: Self) -> Self {
            let modulus = Self::modulus();
            let mut val = lhs.val().wrapping_sub(rhs.val());
            if val >= modulus {
                val = val.wrapping_add(modulus)
            }
            Self::raw(val)
        }

        fn mul_impl(lhs: Self, rhs: Self) -> Self;

        #[inline]
        fn div_impl(lhs: Self, rhs: Self) -> Self {
            Self::mul_impl(lhs, rhs.inv())
        }
    }

    impl<M: Modulus> InternalImplementations for StaticModInt<M> {
        #[inline]
        fn mul_impl(lhs: Self, rhs: Self) -> Self {
            Self::raw((u64::from(lhs.val()) * u64::from(rhs.val()) % u64::from(M::VALUE)) as u32)
        }
    }

    impl<I: Id> InternalImplementations for DynamicModInt<I> {
        #[inline]
        fn mul_impl(lhs: Self, rhs: Self) -> Self {
            I::companion_barrett().with(|bt| Self::raw(bt.borrow().mul(lhs.val, rhs.val)))
        }
    }

    macro_rules! impl_basic_traits {
        () => {};
        (impl <$generic_param:ident : $generic_param_bound:tt> _ for $self:ty; $($rest:tt)*) => {
            impl <$generic_param: $generic_param_bound> Default for $self {
                #[inline]
                fn default() -> Self {
                    Self::default_impl()
                }
            }

            impl <$generic_param: $generic_param_bound> FromStr for $self {
                type Err = Infallible;

                #[inline]
                fn from_str(s: &str) -> Result<Self, Infallible> {
                    Self::from_str_impl(s)
                }
            }

            impl<$generic_param: $generic_param_bound, V: RemEuclidU32> From<V> for $self {
                #[inline]
                fn from(from: V) -> Self {
                    Self::new(from)
                }
            }

            #[allow(clippy::derive_hash_xor_eq)]
            impl<$generic_param: $generic_param_bound> Hash for $self {
                #[inline]
                fn hash<H: Hasher>(&self, state: &mut H) {
                    Self::hash_impl(self, state)
                }
            }

            impl<$generic_param: $generic_param_bound> fmt::Display for $self {
                #[inline]
                fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                    Self::display_impl(self, f)
                }
            }

            impl<$generic_param: $generic_param_bound> fmt::Debug for $self {
                #[inline]
                fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                    Self::debug_impl(self, f)
                }
            }

            impl<$generic_param: $generic_param_bound> Neg for $self {
                type Output = $self;

                #[inline]
                fn neg(self) -> $self {
                    Self::neg_impl(self)
                }
            }

            impl<$generic_param: $generic_param_bound> Neg for &'_ $self {
                type Output = $self;

                #[inline]
                fn neg(self) -> $self {
                    <$self>::neg_impl(*self)
                }
            }

            impl_basic_traits!($($rest)*);
        };
    }

    impl_basic_traits! {
        impl <M: Modulus> _ for StaticModInt<M> ;
        impl <I: Id     > _ for DynamicModInt<I>;
    }

    macro_rules! impl_bin_ops {
        () => {};
        (for<$generic_param:ident : $generic_param_bound:tt> <$lhs_ty:ty> ~ <$rhs_ty:ty> -> $output:ty { { $lhs_body:expr } ~ { $rhs_body:expr } } $($rest:tt)*) => {
            impl <$generic_param: $generic_param_bound> Add<$rhs_ty> for $lhs_ty {
                type Output = $output;

                #[inline]
                fn add(self, rhs: $rhs_ty) -> $output {
                    <$output>::add_impl(apply($lhs_body, self), apply($rhs_body, rhs))
                }
            }

            impl <$generic_param: $generic_param_bound> Sub<$rhs_ty> for $lhs_ty {
                type Output = $output;

                #[inline]
                fn sub(self, rhs: $rhs_ty) -> $output {
                    <$output>::sub_impl(apply($lhs_body, self), apply($rhs_body, rhs))
                }
            }

            impl <$generic_param: $generic_param_bound> Mul<$rhs_ty> for $lhs_ty {
                type Output = $output;

                #[inline]
                fn mul(self, rhs: $rhs_ty) -> $output {
                    <$output>::mul_impl(apply($lhs_body, self), apply($rhs_body, rhs))
                }
            }

            impl <$generic_param: $generic_param_bound> Div<$rhs_ty> for $lhs_ty {
                type Output = $output;

                #[inline]
                fn div(self, rhs: $rhs_ty) -> $output {
                    <$output>::div_impl(apply($lhs_body, self), apply($rhs_body, rhs))
                }
            }

            impl_bin_ops!($($rest)*);
        };
    }

    macro_rules! impl_assign_ops {
        () => {};
        (for<$generic_param:ident : $generic_param_bound:tt> <$lhs_ty:ty> ~= <$rhs_ty:ty> { _ ~= { $rhs_body:expr } } $($rest:tt)*) => {
            impl <$generic_param: $generic_param_bound> AddAssign<$rhs_ty> for $lhs_ty {
                #[inline]
                fn add_assign(&mut self, rhs: $rhs_ty) {
                    *self = *self + apply($rhs_body, rhs);
                }
            }

            impl <$generic_param: $generic_param_bound> SubAssign<$rhs_ty> for $lhs_ty {
                #[inline]
                fn sub_assign(&mut self, rhs: $rhs_ty) {
                    *self = *self - apply($rhs_body, rhs);
                }
            }

            impl <$generic_param: $generic_param_bound> MulAssign<$rhs_ty> for $lhs_ty {
                #[inline]
                fn mul_assign(&mut self, rhs: $rhs_ty) {
                    *self = *self * apply($rhs_body, rhs);
                }
            }

            impl <$generic_param: $generic_param_bound> DivAssign<$rhs_ty> for $lhs_ty {
                #[inline]
                fn div_assign(&mut self, rhs: $rhs_ty) {
                    *self = *self / apply($rhs_body, rhs);
                }
            }

            impl_assign_ops!($($rest)*);
        };
    }

    #[inline]
    fn apply<F: FnOnce(X) -> O, X, O>(f: F, x: X) -> O {
        f(x)
    }

    impl_bin_ops! {
        for<M: Modulus> <StaticModInt<M>     > ~ <StaticModInt<M>     > -> StaticModInt<M>  { { |x| x  } ~ { |x| x  } }
        for<M: Modulus> <StaticModInt<M>     > ~ <&'_ StaticModInt<M> > -> StaticModInt<M>  { { |x| x  } ~ { |&x| x } }
        for<M: Modulus> <&'_ StaticModInt<M> > ~ <StaticModInt<M>     > -> StaticModInt<M>  { { |&x| x } ~ { |x| x  } }
        for<M: Modulus> <&'_ StaticModInt<M> > ~ <&'_ StaticModInt<M> > -> StaticModInt<M>  { { |&x| x } ~ { |&x| x } }
        for<I: Id     > <DynamicModInt<I>    > ~ <DynamicModInt<I>    > -> DynamicModInt<I> { { |x| x  } ~ { |x| x  } }
        for<I: Id     > <DynamicModInt<I>    > ~ <&'_ DynamicModInt<I>> -> DynamicModInt<I> { { |x| x  } ~ { |&x| x } }
        for<I: Id     > <&'_ DynamicModInt<I>> ~ <DynamicModInt<I>    > -> DynamicModInt<I> { { |&x| x } ~ { |x| x  } }
        for<I: Id     > <&'_ DynamicModInt<I>> ~ <&'_ DynamicModInt<I>> -> DynamicModInt<I> { { |&x| x } ~ { |&x| x } }
    }

    impl_assign_ops! {
        for<M: Modulus> <StaticModInt<M> > ~= <StaticModInt<M>     > { _ ~= { |x| x  } }
        for<M: Modulus> <StaticModInt<M> > ~= <&'_ StaticModInt<M> > { _ ~= { |&x| x } }
        for<I: Id     > <DynamicModInt<I>> ~= <DynamicModInt<I>    > { _ ~= { |x| x  } }
        for<I: Id     > <DynamicModInt<I>> ~= <&'_ DynamicModInt<I>> { _ ~= { |&x| x } }
    }

    macro_rules! impl_folding {
        () => {};
        (impl<$generic_param:ident : $generic_param_bound:tt> $trait:ident<_> for $self:ty { fn $method:ident(_) -> _ { _($unit:expr, $op:expr) } } $($rest:tt)*) => {
            impl<$generic_param: $generic_param_bound> $trait<Self> for $self {
                #[inline]
                fn $method<S>(iter: S) -> Self
                where
                    S: Iterator<Item = Self>,
                {
                    iter.fold($unit, $op)
                }
            }

            impl<'a, $generic_param: $generic_param_bound> $trait<&'a Self> for $self {
                #[inline]
                fn $method<S>(iter: S) -> Self
                where
                    S: Iterator<Item = &'a Self>,
                {
                    iter.fold($unit, $op)
                }
            }

            impl_folding!($($rest)*);
        };
    }

    impl_folding! {
        impl<M: Modulus> Sum<_>     for StaticModInt<M>  { fn sum(_)     -> _ { _(Self::raw(0), Add::add) } }
        impl<M: Modulus> Product<_> for StaticModInt<M>  { fn product(_) -> _ { _(Self::raw(1), Mul::mul) } }
        impl<I: Id     > Sum<_>     for DynamicModInt<I> { fn sum(_)     -> _ { _(Self::raw(0), Add::add) } }
        impl<I: Id     > Product<_> for DynamicModInt<I> { fn product(_) -> _ { _(Self::raw(1), Mul::mul) } }
    }

    #[cfg(test)]
    mod tests {
        use crate::modint::ModInt1000000007;

        #[test]
        fn static_modint_new() {
            assert_eq!(0, ModInt1000000007::new(0u32).val);
            assert_eq!(1, ModInt1000000007::new(1u32).val);
            assert_eq!(1, ModInt1000000007::new(1_000_000_008u32).val);

            assert_eq!(0, ModInt1000000007::new(0u64).val);
            assert_eq!(1, ModInt1000000007::new(1u64).val);
            assert_eq!(1, ModInt1000000007::new(1_000_000_008u64).val);

            assert_eq!(0, ModInt1000000007::new(0usize).val);
            assert_eq!(1, ModInt1000000007::new(1usize).val);
            assert_eq!(1, ModInt1000000007::new(1_000_000_008usize).val);

            assert_eq!(0, ModInt1000000007::new(0i64).val);
            assert_eq!(1, ModInt1000000007::new(1i64).val);
            assert_eq!(1, ModInt1000000007::new(1_000_000_008i64).val);
            assert_eq!(1_000_000_006, ModInt1000000007::new(-1i64).val);
        }

        #[test]
        fn static_modint_add() {
            fn add(lhs: u32, rhs: u32) -> u32 {
                (ModInt1000000007::new(lhs) + ModInt1000000007::new(rhs)).val
            }

            assert_eq!(2, add(1, 1));
            assert_eq!(1, add(1_000_000_006, 2));
        }

        #[test]
        fn static_modint_sub() {
            fn sub(lhs: u32, rhs: u32) -> u32 {
                (ModInt1000000007::new(lhs) - ModInt1000000007::new(rhs)).val
            }

            assert_eq!(1, sub(2, 1));
            assert_eq!(1_000_000_006, sub(0, 1));
        }

        #[test]
        fn static_modint_mul() {
            fn mul(lhs: u32, rhs: u32) -> u32 {
                (ModInt1000000007::new(lhs) * ModInt1000000007::new(rhs)).val
            }

            assert_eq!(1, mul(1, 1));
            assert_eq!(4, mul(2, 2));
            assert_eq!(999_999_937, mul(100_000, 100_000));
        }

        #[test]
        fn static_modint_prime_div() {
            fn div(lhs: u32, rhs: u32) -> u32 {
                (ModInt1000000007::new(lhs) / ModInt1000000007::new(rhs)).val
            }

            assert_eq!(0, div(0, 1));
            assert_eq!(1, div(1, 1));
            assert_eq!(1, div(2, 2));
            assert_eq!(23_809_524, div(1, 42));
        }

        #[test]
        fn static_modint_sum() {
            fn sum(values: &[i64]) -> ModInt1000000007 {
                values.iter().copied().map(ModInt1000000007::new).sum()
            }

            assert_eq!(ModInt1000000007::new(-3), sum(&[-1, 2, -3, 4, -5]));
        }

        #[test]
        fn static_modint_product() {
            fn product(values: &[i64]) -> ModInt1000000007 {
                values.iter().copied().map(ModInt1000000007::new).product()
            }

            assert_eq!(ModInt1000000007::new(-120), product(&[-1, 2, -3, 4, -5]));
        }
    }
}
mod scc {
    use crate::internal_scc;

    pub struct SccGraph {
        internal: internal_scc::SccGraph,
    }

    impl SccGraph {
        pub fn new(n: usize) -> Self {
            SccGraph {
                internal: internal_scc::SccGraph::new(n),
            }
        }

        pub fn add_edge(&mut self, from: usize, to: usize) {
            let n = self.internal.num_vertices();
            assert!(from < n);
            assert!(to < n);
            self.internal.add_edge(from, to);
        }

        pub fn scc(&self) -> Vec<Vec<usize>> {
            self.internal.scc()
        }
    }

    #[cfg(test)]
    mod tests {
        use super::*;

        #[test]
        fn test_scc_simple() {
            let mut graph = SccGraph::new(2);
            graph.add_edge(0, 1);
            graph.add_edge(1, 0);
            let scc = graph.scc();
            assert_eq!(scc.len(), 1);
        }

        #[test]
        fn test_scc_self_loop() {
            let mut graph = SccGraph::new(2);
            graph.add_edge(0, 0);
            graph.add_edge(0, 0);
            graph.add_edge(1, 1);
            let scc = graph.scc();
            assert_eq!(scc.len(), 2);
        }

        #[test]
        fn solve_alpc_g_sample1() {
            // https://atcoder.jp/contests/practice2/tasks/practice2_g
            let n: usize = 6;
            let edges = vec![(1, 4), (5, 2), (3, 0), (5, 5), (4, 1), (0, 3), (4, 2)];

            let mut graph = SccGraph::new(n);
            for (u, v) in edges.into_iter() {
                graph.add_edge(u, v);
            }

            let scc = graph.scc();
            assert_eq!(scc, vec![vec![5], vec![1, 4], vec![2], vec![0, 3]]);
        }
    }
}
mod segtree {}
#[allow(clippy::many_single_char_names)]
mod string {
    fn sa_naive<T: Ord>(s: &[T]) -> Vec<usize> {
        let n = s.len();
        let mut sa: Vec<usize> = (0..n).collect();
        sa.sort_by(|&(mut l), &(mut r)| {
            if l == r {
                return std::cmp::Ordering::Equal;
            }
            while l < n && r < n {
                if s[l] != s[r] {
                    return s[l].cmp(&s[r]);
                }
                l += 1;
                r += 1;
            }
            if l == n {
                std::cmp::Ordering::Less
            } else {
                std::cmp::Ordering::Greater
            }
        });
        sa
    }

    fn sa_doubling(s: &[i32]) -> Vec<usize> {
        let n = s.len();
        let mut sa: Vec<usize> = (0..n).collect();
        let mut rnk: Vec<i32> = s.to_vec();
        let mut tmp = vec![0; n];
        let mut k = 1;
        while k < n {
            let cmp = |&x: &usize, &y: &usize| {
                if rnk[x] != rnk[y] {
                    return rnk[x].cmp(&rnk[y]);
                }
                let rx = if x + k < n { rnk[x + k] } else { -1 };
                let ry = if y + k < n { rnk[y + k] } else { -1 };
                rx.cmp(&ry)
            };
            sa.sort_by(cmp);
            tmp[sa[0]] = 0;
            for i in 1..n {
                tmp[sa[i]] = tmp[sa[i - 1]]
                    + if cmp(&sa[i - 1], &sa[i]) == std::cmp::Ordering::Less {
                        1
                    } else {
                        0
                    };
            }
            std::mem::swap(&mut tmp, &mut rnk);
            k *= 2;
        }
        sa
    }

    trait Threshold {
        fn threshold_naive() -> usize;
        fn threshold_doubling() -> usize;
    }

    enum DefaultThreshold {}
    impl Threshold for DefaultThreshold {
        fn threshold_naive() -> usize {
            10
        }
        fn threshold_doubling() -> usize {
            40
        }
    }

    #[allow(clippy::cognitive_complexity)]
    fn sa_is<T: Threshold>(s: &[usize], upper: usize) -> Vec<usize> {
        let n = s.len();
        match n {
            0 => return vec![],
            1 => return vec![0],
            2 => return if s[0] < s[1] { vec![0, 1] } else { vec![1, 0] },
            _ => (),
        }
        if n < T::threshold_naive() {
            return sa_naive(s);
        }
        if n < T::threshold_doubling() {
            let s: Vec<i32> = s.iter().map(|&x| x as i32).collect();
            return sa_doubling(&s);
        }
        let mut sa = vec![0; n];
        let mut ls = vec![false; n];
        for i in (0..n - 1).rev() {
            ls[i] = if s[i] == s[i + 1] {
                ls[i + 1]
            } else {
                s[i] < s[i + 1]
            };
        }
        let mut sum_l = vec![0; upper + 1];
        let mut sum_s = vec![0; upper + 1];
        for i in 0..n {
            if !ls[i] {
                sum_s[s[i]] += 1;
            } else {
                sum_l[s[i] + 1] += 1;
            }
        }
        for i in 0..=upper {
            sum_s[i] += sum_l[i];
            if i < upper {
                sum_l[i + 1] += sum_s[i];
            }
        }

        // sa's origin is 1.
        let induce = |sa: &mut [usize], lms: &[usize]| {
            for elem in sa.iter_mut() {
                *elem = 0;
            }
            let mut buf = sum_s.clone();
            for &d in lms {
                if d == n {
                    continue;
                }
                let old = buf[s[d]];
                buf[s[d]] += 1;
                sa[old] = d + 1;
            }
            buf.copy_from_slice(&sum_l);
            let old = buf[s[n - 1]];
            buf[s[n - 1]] += 1;
            sa[old] = n;
            for i in 0..n {
                let v = sa[i];
                if v >= 2 && !ls[v - 2] {
                    let old = buf[s[v - 2]];
                    buf[s[v - 2]] += 1;
                    sa[old] = v - 1;
                }
            }
            buf.copy_from_slice(&sum_l);
            for i in (0..n).rev() {
                let v = sa[i];
                if v >= 2 && ls[v - 2] {
                    buf[s[v - 2] + 1] -= 1;
                    sa[buf[s[v - 2] + 1]] = v - 1;
                }
            }
        };
        // origin: 1
        let mut lms_map = vec![0; n + 1];
        let mut m = 0;
        for i in 1..n {
            if !ls[i - 1] && ls[i] {
                lms_map[i] = m + 1;
                m += 1;
            }
        }
        let mut lms = Vec::with_capacity(m);
        for i in 1..n {
            if !ls[i - 1] && ls[i] {
                lms.push(i);
            }
        }
        assert_eq!(lms.len(), m);
        induce(&mut sa, &lms);

        if m > 0 {
            let mut sorted_lms = Vec::with_capacity(m);
            for &v in &sa {
                if lms_map[v - 1] != 0 {
                    sorted_lms.push(v - 1);
                }
            }
            let mut rec_s = vec![0; m];
            let mut rec_upper = 0;
            rec_s[lms_map[sorted_lms[0]] - 1] = 0;
            for i in 1..m {
                let mut l = sorted_lms[i - 1];
                let mut r = sorted_lms[i];
                let end_l = if lms_map[l] < m { lms[lms_map[l]] } else { n };
                let end_r = if lms_map[r] < m { lms[lms_map[r]] } else { n };
                let same = if end_l - l != end_r - r {
                    false
                } else {
                    while l < end_l {
                        if s[l] != s[r] {
                            break;
                        }
                        l += 1;
                        r += 1;
                    }
                    l != n && s[l] == s[r]
                };
                if !same {
                    rec_upper += 1;
                }
                rec_s[lms_map[sorted_lms[i]] - 1] = rec_upper;
            }

            let rec_sa = sa_is::<T>(&rec_s, rec_upper);
            for i in 0..m {
                sorted_lms[i] = lms[rec_sa[i]];
            }
            induce(&mut sa, &mut sorted_lms);
        }
        for elem in sa.iter_mut() {
            *elem -= 1;
        }
        sa
    }

    fn sa_is_i32<T: Threshold>(s: &[i32], upper: i32) -> Vec<usize> {
        let s: Vec<usize> = s.iter().map(|&x| x as usize).collect();
        sa_is::<T>(&s, upper as usize)
    }

    pub fn suffix_array_manual(s: &[i32], upper: i32) -> Vec<usize> {
        assert!(upper >= 0);
        for &elem in s {
            assert!(0 <= elem && elem <= upper);
        }
        sa_is_i32::<DefaultThreshold>(s, upper)
    }

    pub fn suffix_array_arbitrary<T: Ord>(s: &[T]) -> Vec<usize> {
        let n = s.len();
        let mut idx: Vec<usize> = (0..n).collect();
        idx.sort_by_key(|&i| &s[i]);
        let mut s2 = vec![0; n];
        let mut now = 0;
        for i in 0..n {
            if i > 0 && s[idx[i - 1]] != s[idx[i]] {
                now += 1;
            }
            s2[idx[i]] = now;
        }
        sa_is_i32::<DefaultThreshold>(&s2, now)
    }

    pub fn suffix_array(s: &str) -> Vec<usize> {
        let s2: Vec<usize> = s.bytes().map(|x| x as usize).collect();
        sa_is::<DefaultThreshold>(&s2, 255)
    }

    // Reference:
    // T. Kasai, G. Lee, H. Arimura, S. Arikawa, and K. Park,
    // Linear-Time Longest-Common-Prefix Computation in Suffix Arrays and Its
    // Applications
    pub fn lcp_array_arbitrary<T: Ord>(s: &[T], sa: &[usize]) -> Vec<usize> {
        let n = s.len();
        assert!(n >= 1);
        let mut rnk = vec![0; n];
        for i in 0..n {
            rnk[sa[i]] = i;
        }
        let mut lcp = vec![0; n - 1];
        let mut h = 0;
        for i in 0..n - 1 {
            if h > 0 {
                h -= 1;
            }
            if rnk[i] == 0 {
                continue;
            }
            let j = sa[rnk[i] - 1];
            while j + h < n && i + h < n {
                if s[j + h] != s[i + h] {
                    break;
                }
                h += 1;
            }
            lcp[rnk[i] - 1] = h;
        }
        lcp
    }

    pub fn lcp_array(s: &str, sa: &[usize]) -> Vec<usize> {
        let s: &[u8] = s.as_bytes();
        lcp_array_arbitrary(s, sa)
    }

    // Reference:
    // D. Gusfield,
    // Algorithms on Strings, Trees, and Sequences: Computer Science and
    // Computational Biology
    pub fn z_algorithm_arbitrary<T: Ord>(s: &[T]) -> Vec<usize> {
        let n = s.len();
        if n == 0 {
            return vec![];
        }
        let mut z = vec![0; n];
        z[0] = 0;
        let mut j = 0;
        for i in 1..n {
            let mut k = if j + z[j] <= i {
                0
            } else {
                std::cmp::min(j + z[j] - i, z[i - j])
            };
            while i + k < n && s[k] == s[i + k] {
                k += 1;
            }
            z[i] = k;
            if j + z[j] < i + z[i] {
                j = i;
            }
        }
        z[0] = n;
        z
    }

    pub fn z_algorithm(s: &str) -> Vec<usize> {
        let s: &[u8] = s.as_bytes();
        z_algorithm_arbitrary(s)
    }

    #[cfg(test)]
    mod tests {
        use super::*;

        enum ZeroThreshold {}
        impl Threshold for ZeroThreshold {
            fn threshold_naive() -> usize {
                0
            }
            fn threshold_doubling() -> usize {
                0
            }
        }

        fn verify_all(str: &str, expected_array: &[usize]) {
            let array: Vec<i32> = str.bytes().map(|x| x as i32).collect();
            let sa = sa_doubling(&array);
            assert_eq!(sa, expected_array);
            let sa_naive = sa_naive(&array);
            assert_eq!(sa_naive, expected_array);
            let sa_is = sa_is_i32::<ZeroThreshold>(&array, 255);
            assert_eq!(sa_is, expected_array);

            let sa_str = suffix_array(str);
            assert_eq!(sa_str, expected_array);
        }

        #[test]
        fn test_sa_0() {
            let array = vec![0, 1, 2, 3, 4];
            let sa = sa_doubling(&array);
            assert_eq!(sa, vec![0, 1, 2, 3, 4]);
        }

        #[test]
        fn test_sa_1() {
            let str = "abracadabra";
            verify_all(str, &[10, 7, 0, 3, 5, 8, 1, 4, 6, 9, 2]);
        }

        #[test]
        fn test_sa_2() {
            let str = "mmiissiissiippii"; // an example taken from https://mametter.hatenablog.com/entry/20180130/p1
            verify_all(str, &[15, 14, 10, 6, 2, 11, 7, 3, 1, 0, 13, 12, 9, 5, 8, 4]);
        }

        #[test]
        fn test_lcp_0() {
            let str = "abracadabra";
            let sa = suffix_array(str);
            let lcp = lcp_array(str, &sa);
            assert_eq!(lcp, &[1, 4, 1, 1, 0, 3, 0, 0, 0, 2]);
        }

        #[test]
        fn test_lcp_1() {
            let str = "mmiissiissiippii"; // an example taken from https://mametter.hatenablog.com/entry/20180130/p1
            let sa = suffix_array(str);
            let lcp = lcp_array(str, &sa);
            assert_eq!(lcp, &[1, 2, 2, 6, 1, 1, 5, 0, 1, 0, 1, 0, 3, 1, 4]);
        }

        #[test]
        fn test_z_0() {
            let str = "abracadabra";
            let lcp = z_algorithm(str);
            assert_eq!(lcp, &[11, 0, 0, 1, 0, 1, 0, 4, 0, 0, 1]);
        }

        #[test]
        fn test_z_1() {
            let str = "ababababa";
            let lcp = z_algorithm(str);
            assert_eq!(lcp, &[9, 0, 7, 0, 5, 0, 3, 0, 1]);
        }
    }
}
mod twosat {
    use crate::internal_scc;

    pub struct TwoSat {
        n: usize,
        scc: internal_scc::SccGraph,
        answer: Vec<bool>,
    }
    impl TwoSat {
        pub fn new(n: usize) -> Self {
            TwoSat {
                n,
                answer: vec![false; n],
                scc: internal_scc::SccGraph::new(2 * n),
            }
        }
        pub fn add_clause(&mut self, i: usize, f: bool, j: usize, g: bool) {
            assert!(i < self.n && j < self.n);
            self.scc.add_edge(2 * i + !f as usize, 2 * j + g as usize);
            self.scc.add_edge(2 * j + !g as usize, 2 * i + f as usize);
        }
        pub fn satisfiable(&mut self) -> bool {
            let id = self.scc.scc_ids().1;
            for i in 0..self.n {
                if id[2 * i] == id[2 * i + 1] {
                    return false;
                }
                self.answer[i] = id[2 * i] < id[2 * i + 1];
            }
            true
        }
        pub fn answer(&self) -> &[bool] {
            &self.answer
        }
    }

    #[cfg(test)]
    mod tests {
        #![allow(clippy::many_single_char_names)]
        use super::*;
        #[test]
        fn solve_alpc_h_sample1() {
            // https://atcoder.jp/contests/practice2/tasks/practice2_h

            let (n, d) = (3, 2);
            let x = [1, 2, 0i32];
            let y = [4, 5, 6];

            let mut t = TwoSat::new(n);

            for i in 0..n {
                for j in i + 1..n {
                    if (x[i] - x[j]).abs() < d {
                        t.add_clause(i, false, j, false);
                    }
                    if (x[i] - y[j]).abs() < d {
                        t.add_clause(i, false, j, true);
                    }
                    if (y[i] - x[j]).abs() < d {
                        t.add_clause(i, true, j, false);
                    }
                    if (y[i] - y[j]).abs() < d {
                        t.add_clause(i, true, j, true);
                    }
                }
            }
            assert!(t.satisfiable());
            let answer = t.answer();
            let mut res = vec![];
            for (i, &v) in answer.iter().enumerate() {
                if v {
                    res.push(x[i])
                } else {
                    res.push(y[i]);
                }
            }

            //Check the min distance between flags
            res.sort();
            let mut min_distance = i32::max_value();
            for i in 1..res.len() {
                min_distance = std::cmp::min(min_distance, res[i] - res[i - 1]);
            }
            assert!(min_distance >= d);
        }

        #[test]
        fn solve_alpc_h_sample2() {
            // https://atcoder.jp/contests/practice2/tasks/practice2_h

            let (n, d) = (3, 3);
            let x = [1, 2, 0i32];
            let y = [4, 5, 6];

            let mut t = TwoSat::new(n);

            for i in 0..n {
                for j in i + 1..n {
                    if (x[i] - x[j]).abs() < d {
                        t.add_clause(i, false, j, false);
                    }
                    if (x[i] - y[j]).abs() < d {
                        t.add_clause(i, false, j, true);
                    }
                    if (y[i] - x[j]).abs() < d {
                        t.add_clause(i, true, j, false);
                    }
                    if (y[i] - y[j]).abs() < d {
                        t.add_clause(i, true, j, true);
                    }
                }
            }
            assert!(!t.satisfiable());
        }
    }
}
pub(crate) mod internal_bit {
    // Skipped:
    //
    // - `bsf` = `__builtin_ctz`: is equivalent to `{integer}::trailing_zeros`

    #[allow(dead_code)]
    pub(crate) fn ceil_pow2(n: u32) -> u32 {
        32 - n.saturating_sub(1).leading_zeros()
    }

    #[cfg(test)]
    mod tests {
        #[test]
        fn ceil_pow2() {
            // https://github.com/atcoder/ac-library/blob/2088c8e2431c3f4d29a2cfabc6529fe0a0586c48/test/unittest/bit_test.cpp
            assert_eq!(0, super::ceil_pow2(0));
            assert_eq!(0, super::ceil_pow2(1));
            assert_eq!(1, super::ceil_pow2(2));
            assert_eq!(2, super::ceil_pow2(3));
            assert_eq!(2, super::ceil_pow2(4));
            assert_eq!(3, super::ceil_pow2(5));
            assert_eq!(3, super::ceil_pow2(6));
            assert_eq!(3, super::ceil_pow2(7));
            assert_eq!(3, super::ceil_pow2(8));
            assert_eq!(4, super::ceil_pow2(9));
            assert_eq!(30, super::ceil_pow2(1 << 30));
            assert_eq!(31, super::ceil_pow2((1 << 30) + 1));

            assert_eq!(32, super::ceil_pow2(u32::max_value()));
        }
    }
}
pub(crate) mod internal_math {
    // remove this after dependencies has been added
    #![allow(dead_code)]
    use std::mem::swap;

    /// # Arguments
    /// * `m` `1 <= m`
    ///
    /// # Returns
    /// x mod m
    /* const */
    pub(crate) fn safe_mod(mut x: i64, m: i64) -> i64 {
        x %= m;
        if x < 0 {
            x += m;
        }
        x
    }

    /// Fast modular by barrett reduction
    /// Reference: https://en.wikipedia.org/wiki/Barrett_reduction
    /// NOTE: reconsider after Ice Lake
    pub(crate) struct Barrett {
        pub(crate) _m: u32,
        pub(crate) im: u64,
    }

    impl Barrett {
        /// # Arguments
        /// * `m` `1 <= m`
        /// (Note: `m <= 2^31` should also hold, which is undocumented in the original library.
        /// See the [pull reqeust commment](https://github.com/rust-lang-ja/ac-library-rs/pull/3#discussion_r484661007)
        /// for more details.)
        pub(crate) fn new(m: u32) -> Barrett {
            Barrett {
                _m: m,
                im: (-1i64 as u64 / m as u64).wrapping_add(1),
            }
        }

        /// # Returns
        /// `m`
        pub(crate) fn umod(&self) -> u32 {
            self._m
        }

        /// # Parameters
        /// * `a` `0 <= a < m`
        /// * `b` `0 <= b < m`
        ///
        /// # Returns
        /// a * b % m
        #[allow(clippy::many_single_char_names)]
        pub(crate) fn mul(&self, a: u32, b: u32) -> u32 {
            // [1] m = 1
            // a = b = im = 0, so okay

            // [2] m >= 2
            // im = ceil(2^64 / m)
            // -> im * m = 2^64 + r (0 <= r < m)
            // let z = a*b = c*m + d (0 <= c, d < m)
            // a*b * im = (c*m + d) * im = c*(im*m) + d*im = c*2^64 + c*r + d*im
            // c*r + d*im < m * m + m * im < m * m + 2^64 + m <= 2^64 + m * (m + 1) < 2^64 * 2
            // ((ab * im) >> 64) == c or c + 1
            let mut z = a as u64;
            z *= b as u64;
            let x = (((z as u128) * (self.im as u128)) >> 64) as u64;
            let mut v = z.wrapping_sub(x.wrapping_mul(self._m as u64)) as u32;
            if self._m <= v {
                v = v.wrapping_add(self._m);
            }
            v
        }
    }

    /// # Parameters
    /// * `n` `0 <= n`
    /// * `m` `1 <= m`
    ///
    /// # Returns
    /// `(x ** n) % m`
    /* const */
    #[allow(clippy::many_single_char_names)]
    pub(crate) fn pow_mod(x: i64, mut n: i64, m: i32) -> i64 {
        if m == 1 {
            return 0;
        }
        let _m = m as u32;
        let mut r: u64 = 1;
        let mut y: u64 = safe_mod(x, m as i64) as u64;
        while n != 0 {
            if (n & 1) > 0 {
                r = (r * y) % (_m as u64);
            }
            y = (y * y) % (_m as u64);
            n >>= 1;
        }
        r as i64
    }

    /// Reference:
    /// M. Forisek and J. Jancina,
    /// Fast Primality Testing for Integers That Fit into a Machine Word
    ///
    /// # Parameters
    /// * `n` `0 <= n`
    /* const */
    pub(crate) fn is_prime(n: i32) -> bool {
        let n = n as i64;
        match n {
            _ if n <= 1 => return false,
            2 | 7 | 61 => return true,
            _ if n % 2 == 0 => return false,
            _ => {}
        }
        let mut d = n - 1;
        while d % 2 == 0 {
            d /= 2;
        }
        for &a in &[2, 7, 61] {
            let mut t = d;
            let mut y = pow_mod(a, t, n as i32);
            while t != n - 1 && y != 1 && y != n - 1 {
                y = y * y % n;
                t <<= 1;
            }
            if y != n - 1 && t % 2 == 0 {
                return false;
            }
        }
        true
    }

    // omitted
    // template <int n> constexpr bool is_prime = is_prime_constexpr(n);

    /// # Parameters
    /// * `b` `1 <= b`
    ///
    /// # Returns
    /// (g, x) s.t. g = gcd(a, b), xa = g (mod b), 0 <= x < b/g
    /* const */
    #[allow(clippy::many_single_char_names)]
    pub(crate) fn inv_gcd(a: i64, b: i64) -> (i64, i64) {
        let a = safe_mod(a, b);
        if a == 0 {
            return (b, 0);
        }

        // Contracts:
        // [1] s - m0 * a = 0 (mod b)
        // [2] t - m1 * a = 0 (mod b)
        // [3] s * |m1| + t * |m0| <= b
        let mut s = b;
        let mut t = a;
        let mut m0 = 0;
        let mut m1 = 1;

        while t != 0 {
            let u = s / t;
            s -= t * u;
            m0 -= m1 * u; // |m1 * u| <= |m1| * s <= b

            // [3]:
            // (s - t * u) * |m1| + t * |m0 - m1 * u|
            // <= s * |m1| - t * u * |m1| + t * (|m0| + |m1| * u)
            // = s * |m1| + t * |m0| <= b

            swap(&mut s, &mut t);
            swap(&mut m0, &mut m1);
        }
        // by [3]: |m0| <= b/g
        // by g != b: |m0| < b/g
        if m0 < 0 {
            m0 += b / s;
        }
        (s, m0)
    }

    /// Compile time (currently not) primitive root
    /// @param m must be prime
    /// @return primitive root (and minimum in now)
    /* const */
    pub(crate) fn primitive_root(m: i32) -> i32 {
        match m {
            2 => return 1,
            167_772_161 => return 3,
            469_762_049 => return 3,
            754_974_721 => return 11,
            998_244_353 => return 3,
            _ => {}
        }

        let mut divs = [0; 20];
        divs[0] = 2;
        let mut cnt = 1;
        let mut x = (m - 1) / 2;
        while x % 2 == 0 {
            x /= 2;
        }
        for i in (3..std::i32::MAX).step_by(2) {
            if i as i64 * i as i64 > x as i64 {
                break;
            }
            if x % i == 0 {
                divs[cnt] = i;
                cnt += 1;
                while x % i == 0 {
                    x /= i;
                }
            }
        }
        if x > 1 {
            divs[cnt] = x;
            cnt += 1;
        }
        let mut g = 2;
        loop {
            if (0..cnt).all(|i| pow_mod(g, ((m - 1) / divs[i]) as i64, m) != 1) {
                break g as i32;
            }
            g += 1;
        }
    }
    // omitted
    // template <int m> constexpr int primitive_root = primitive_root_constexpr(m);

    #[cfg(test)]
    mod tests {
        #![allow(clippy::unreadable_literal)]
        #![allow(clippy::cognitive_complexity)]
        use crate::internal_math::{inv_gcd, is_prime, pow_mod, primitive_root, safe_mod, Barrett};
        use std::collections::HashSet;

        #[test]
        fn test_safe_mod() {
            assert_eq!(safe_mod(0, 3), 0);
            assert_eq!(safe_mod(1, 3), 1);
            assert_eq!(safe_mod(2, 3), 2);
            assert_eq!(safe_mod(3, 3), 0);
            assert_eq!(safe_mod(4, 3), 1);
            assert_eq!(safe_mod(5, 3), 2);
            assert_eq!(safe_mod(73, 11), 7);
            assert_eq!(safe_mod(2306249155046129918, 6620319213327), 1374210749525);

            assert_eq!(safe_mod(-1, 3), 2);
            assert_eq!(safe_mod(-2, 3), 1);
            assert_eq!(safe_mod(-3, 3), 0);
            assert_eq!(safe_mod(-4, 3), 2);
            assert_eq!(safe_mod(-5, 3), 1);
            assert_eq!(safe_mod(-7170500492396019511, 777567337), 333221848);
        }

        #[test]
        fn test_barrett() {
            let b = Barrett::new(7);
            assert_eq!(b.umod(), 7);
            assert_eq!(b.mul(2, 3), 6);
            assert_eq!(b.mul(4, 6), 3);
            assert_eq!(b.mul(5, 0), 0);

            let b = Barrett::new(998244353);
            assert_eq!(b.umod(), 998244353);
            assert_eq!(b.mul(2, 3), 6);
            assert_eq!(b.mul(3141592, 653589), 919583920);
            assert_eq!(b.mul(323846264, 338327950), 568012980);

            // make `z - x * self._m as u64` overflow.
            // Thanks @koba-e964 (at https://github.com/rust-lang-ja/ac-library-rs/pull/3#discussion_r484932161)
            let b = Barrett::new(2147483647);
            assert_eq!(b.umod(), 2147483647);
            assert_eq!(b.mul(1073741824, 2147483645), 2147483646);
        }

        #[test]
        fn test_pow_mod() {
            assert_eq!(pow_mod(0, 0, 1), 0);
            assert_eq!(pow_mod(0, 0, 3), 1);
            assert_eq!(pow_mod(0, 0, 723), 1);
            assert_eq!(pow_mod(0, 0, 998244353), 1);
            assert_eq!(pow_mod(0, 0, i32::max_value()), 1);

            assert_eq!(pow_mod(0, 1, 1), 0);
            assert_eq!(pow_mod(0, 1, 3), 0);
            assert_eq!(pow_mod(0, 1, 723), 0);
            assert_eq!(pow_mod(0, 1, 998244353), 0);
            assert_eq!(pow_mod(0, 1, i32::max_value()), 0);

            assert_eq!(pow_mod(0, i64::max_value(), 1), 0);
            assert_eq!(pow_mod(0, i64::max_value(), 3), 0);
            assert_eq!(pow_mod(0, i64::max_value(), 723), 0);
            assert_eq!(pow_mod(0, i64::max_value(), 998244353), 0);
            assert_eq!(pow_mod(0, i64::max_value(), i32::max_value()), 0);

            assert_eq!(pow_mod(1, 0, 1), 0);
            assert_eq!(pow_mod(1, 0, 3), 1);
            assert_eq!(pow_mod(1, 0, 723), 1);
            assert_eq!(pow_mod(1, 0, 998244353), 1);
            assert_eq!(pow_mod(1, 0, i32::max_value()), 1);

            assert_eq!(pow_mod(1, 1, 1), 0);
            assert_eq!(pow_mod(1, 1, 3), 1);
            assert_eq!(pow_mod(1, 1, 723), 1);
            assert_eq!(pow_mod(1, 1, 998244353), 1);
            assert_eq!(pow_mod(1, 1, i32::max_value()), 1);

            assert_eq!(pow_mod(1, i64::max_value(), 1), 0);
            assert_eq!(pow_mod(1, i64::max_value(), 3), 1);
            assert_eq!(pow_mod(1, i64::max_value(), 723), 1);
            assert_eq!(pow_mod(1, i64::max_value(), 998244353), 1);
            assert_eq!(pow_mod(1, i64::max_value(), i32::max_value()), 1);

            assert_eq!(pow_mod(i64::max_value(), 0, 1), 0);
            assert_eq!(pow_mod(i64::max_value(), 0, 3), 1);
            assert_eq!(pow_mod(i64::max_value(), 0, 723), 1);
            assert_eq!(pow_mod(i64::max_value(), 0, 998244353), 1);
            assert_eq!(pow_mod(i64::max_value(), 0, i32::max_value()), 1);

            assert_eq!(pow_mod(i64::max_value(), i64::max_value(), 1), 0);
            assert_eq!(pow_mod(i64::max_value(), i64::max_value(), 3), 1);
            assert_eq!(pow_mod(i64::max_value(), i64::max_value(), 723), 640);
            assert_eq!(
                pow_mod(i64::max_value(), i64::max_value(), 998244353),
                683296792
            );
            assert_eq!(
                pow_mod(i64::max_value(), i64::max_value(), i32::max_value()),
                1
            );

            assert_eq!(pow_mod(2, 3, 1_000_000_007), 8);
            assert_eq!(pow_mod(5, 7, 1_000_000_007), 78125);
            assert_eq!(pow_mod(123, 456, 1_000_000_007), 565291922);
        }

        #[test]
        fn test_is_prime() {
            assert!(!is_prime(0));
            assert!(!is_prime(1));
            assert!(is_prime(2));
            assert!(is_prime(3));
            assert!(!is_prime(4));
            assert!(is_prime(5));
            assert!(!is_prime(6));
            assert!(is_prime(7));
            assert!(!is_prime(8));
            assert!(!is_prime(9));

            // assert!(is_prime(57));
            assert!(!is_prime(57));
            assert!(!is_prime(58));
            assert!(is_prime(59));
            assert!(!is_prime(60));
            assert!(is_prime(61));
            assert!(!is_prime(62));

            assert!(!is_prime(701928443));
            assert!(is_prime(998244353));
            assert!(!is_prime(1_000_000_000));
            assert!(is_prime(1_000_000_007));

            assert!(is_prime(i32::max_value()));
        }

        #[test]
        fn test_is_prime_sieve() {
            let n = 1_000_000;
            let mut prime = vec![true; n];
            prime[0] = false;
            prime[1] = false;
            for i in 0..n {
                assert_eq!(prime[i], is_prime(i as i32));
                if prime[i] {
                    for j in (2 * i..n).step_by(i) {
                        prime[j] = false;
                    }
                }
            }
        }

        #[test]
        fn test_inv_gcd() {
            for &(a, b, g) in &[
                (0, 1, 1),
                (0, 4, 4),
                (0, 7, 7),
                (2, 3, 1),
                (-2, 3, 1),
                (4, 6, 2),
                (-4, 6, 2),
                (13, 23, 1),
                (57, 81, 3),
                (12345, 67890, 15),
                (-3141592 * 6535, 3141592 * 8979, 3141592),
                (i64::max_value(), i64::max_value(), i64::max_value()),
                (i64::min_value(), i64::max_value(), 1),
            ] {
                let (g_, x) = inv_gcd(a, b);
                assert_eq!(g, g_);
                let b_ = b as i128;
                assert_eq!(((x as i128 * a as i128) % b_ + b_) % b_, g as i128 % b_);
            }
        }

        #[test]
        fn test_primitive_root() {
            for &p in &[
                2,
                3,
                5,
                7,
                233,
                200003,
                998244353,
                1_000_000_007,
                i32::max_value(),
            ] {
                assert!(is_prime(p));
                let g = primitive_root(p);
                if p != 2 {
                    assert_ne!(g, 1);
                }

                let q = p - 1;
                for i in (2..i32::max_value()).take_while(|i| i * i <= q) {
                    if q % i != 0 {
                        break;
                    }
                    for &r in &[i, q / i] {
                        assert_ne!(pow_mod(g as i64, r as i64, p), 1);
                    }
                }
                assert_eq!(pow_mod(g as i64, q as i64, p), 1);

                if p < 1_000_000 {
                    assert_eq!(
                        (0..p - 1)
                            .scan(1, |i, _| {
                                *i = *i * g % p;
                                Some(*i)
                            })
                            .collect::<HashSet<_>>()
                            .len() as i32,
                        p - 1
                    );
                }
            }
        }
    }
}
pub(crate) mod internal_queue {
    #![allow(dead_code)]

    #[derive(Default)]
    pub(crate) struct SimpleQueue<T> {
        payload: Vec<T>,
        pos: usize,
    }

    impl<T> SimpleQueue<T> {
        pub(crate) fn reserve(&mut self, n: usize) {
            if n > self.payload.len() {
                self.payload.reserve(n - self.payload.len());
            }
        }

        pub(crate) fn size(&self) -> usize {
            self.payload.len() - self.pos
        }

        pub(crate) fn empty(&self) -> bool {
            self.pos == self.payload.len()
        }

        pub(crate) fn push(&mut self, t: T) {
            self.payload.push(t);
        }

        // Do we need mutable version?
        pub(crate) fn front(&self) -> Option<&T> {
            if self.pos < self.payload.len() {
                Some(&self.payload[self.pos])
            } else {
                None
            }
        }

        pub(crate) fn clear(&mut self) {
            self.payload.clear();
            self.pos = 0;
        }

        pub(crate) fn pop(&mut self) -> Option<&T> {
            if self.pos < self.payload.len() {
                self.pos += 1;
                Some(&self.payload[self.pos - 1])
            } else {
                None
            }
        }
    }

    #[cfg(test)]
    mod test {
        use crate::internal_queue::SimpleQueue;

        #[allow(clippy::cognitive_complexity)]
        #[test]
        fn test_simple_queue() {
            let mut queue = SimpleQueue::default();

            assert_eq!(queue.size(), 0);
            assert!(queue.empty());
            assert!(queue.front().is_none());
            assert!(queue.pop().is_none());

            queue.push(123);

            assert_eq!(queue.size(), 1);
            assert!(!queue.empty());
            assert_eq!(queue.front(), Some(&123));

            queue.push(456);

            assert_eq!(queue.size(), 2);
            assert!(!queue.empty());
            assert_eq!(queue.front(), Some(&123));

            assert_eq!(queue.pop(), Some(&123));
            assert_eq!(queue.size(), 1);
            assert!(!queue.empty());
            assert_eq!(queue.front(), Some(&456));

            queue.push(789);
            queue.push(789);
            queue.push(456);
            queue.push(456);

            assert_eq!(queue.size(), 5);
            assert!(!queue.empty());
            assert_eq!(queue.front(), Some(&456));

            assert_eq!(queue.pop(), Some(&456));
            assert_eq!(queue.size(), 4);
            assert!(!queue.empty());
            assert_eq!(queue.front(), Some(&789));

            queue.clear();

            assert_eq!(queue.size(), 0);
            assert!(queue.empty());
            assert!(queue.front().is_none());
            assert!(queue.pop().is_none());
        }
    }
}
pub(crate) mod internal_scc {
    pub struct Csr<E> {
        start: Vec<usize>,
        elist: Vec<E>,
    }

    impl<E> Csr<E>
    where
        E: Copy,
    {
        pub fn new(n: usize, edges: &[(usize, E)], init: E) -> Self {
            let mut csr = Csr {
                start: vec![0; n + 1],
                elist: vec![init; edges.len()],
            };
            for e in edges.iter() {
                csr.start[e.0 + 1] += 1;
            }
            for i in 1..=n {
                csr.start[i] += csr.start[i - 1];
            }
            let mut counter = csr.start.clone();
            for e in edges.iter() {
                csr.elist[counter[e.0]] = e.1;
                counter[e.0] += 1;
            }
            csr
        }
    }

    #[derive(Copy, Clone)]
    struct _Edge {
        to: usize,
    }

    /// Reference:
    /// R. Tarjan,
    /// Depth-First Search and Linear Graph Algorithms
    pub struct SccGraph {
        n: usize,
        edges: Vec<(usize, _Edge)>,
    }

    impl SccGraph {
        pub fn new(n: usize) -> Self {
            SccGraph { n, edges: vec![] }
        }

        pub fn num_vertices(&self) -> usize {
            self.n
        }

        pub fn add_edge(&mut self, from: usize, to: usize) {
            self.edges.push((from, _Edge { to }));
        }

        /// return pair of (# of scc, scc id)
        pub fn scc_ids(&self) -> (usize, Vec<usize>) {
            // In C++ ac-library, this function is implemented by using recursive lambda functions.
            // Instead, we use fn and struct for capturing environments.
            struct _Env {
                g: Csr<_Edge>,
                now_ord: usize,
                group_num: usize,
                visited: Vec<usize>,
                low: Vec<usize>,
                ord: Vec<Option<usize>>,
                ids: Vec<usize>,
            }
            let mut env = _Env {
                g: Csr::new(self.n, &self.edges, _Edge { to: 0 }),
                now_ord: 0,
                group_num: 0,
                visited: Vec::with_capacity(self.n),
                low: vec![0; self.n],
                ord: vec![None; self.n],
                ids: vec![0; self.n],
            };

            fn dfs(v: usize, n: usize, env: &mut _Env) {
                env.low[v] = env.now_ord;
                env.ord[v] = Some(env.now_ord);
                env.now_ord += 1;
                env.visited.push(v);

                for i in env.g.start[v]..env.g.start[v + 1] {
                    let to = env.g.elist[i].to;
                    if let Some(x) = env.ord[to] {
                        env.low[v] = std::cmp::min(env.low[v], x);
                    } else {
                        dfs(to, n, env);
                        env.low[v] = std::cmp::min(env.low[v], env.low[to]);
                    }
                }
                if env.low[v] == env.ord[v].unwrap() {
                    loop {
                        let u = *env.visited.last().unwrap();
                        env.visited.pop();
                        env.ord[u] = Some(n);
                        env.ids[u] = env.group_num;
                        if u == v {
                            break;
                        }
                    }
                    env.group_num += 1;
                }
            }
            for i in 0..self.n {
                if env.ord[i].is_none() {
                    dfs(i, self.n, &mut env);
                }
            }
            for x in env.ids.iter_mut() {
                *x = env.group_num - 1 - *x;
            }
            (env.group_num, env.ids)
        }

        pub fn scc(&self) -> Vec<Vec<usize>> {
            let ids = self.scc_ids();
            let group_num = ids.0;
            let mut counts = vec![0usize; group_num];
            for &x in ids.1.iter() {
                counts[x] += 1;
            }
            let mut groups: Vec<Vec<usize>> = (0..ids.0).map(|_| vec![]).collect();
            for i in 0..group_num {
                groups[i].reserve(counts[i]);
            }
            for i in 0..self.n {
                groups[ids.1[i]].push(i);
            }
            groups
        }
    }
}
pub(crate) mod internal_type_traits {
    use std::{
        fmt,
        iter::{Product, Sum},
        ops::{
            Add, AddAssign, BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Div,
            DivAssign, Mul, MulAssign, Not, Rem, RemAssign, Shl, ShlAssign, Shr, ShrAssign, Sub,
            SubAssign,
        },
    };

    // Skipped:
    //
    // - `is_signed_int_t<T>`   (probably won't be used directly in `modint.rs`)
    // - `is_unsigned_int_t<T>` (probably won't be used directly in `modint.rs`)
    // - `to_unsigned_t<T>`     (not used in `fenwicktree.rs`)

    /// Corresponds to `std::is_integral` in C++.
    // We will remove unnecessary bounds later.
    //
    // Maybe we should rename this to `PrimitiveInteger` or something, as it probably won't be used in the
    // same way as the original ACL.
    pub trait Integral:
        'static
        + Send
        + Sync
        + Copy
        + Ord
        + Not<Output = Self>
        + Add<Output = Self>
        + Sub<Output = Self>
        + Mul<Output = Self>
        + Div<Output = Self>
        + Rem<Output = Self>
        + AddAssign
        + SubAssign
        + MulAssign
        + DivAssign
        + RemAssign
        + Sum
        + Product
        + BitOr<Output = Self>
        + BitAnd<Output = Self>
        + BitXor<Output = Self>
        + BitOrAssign
        + BitAndAssign
        + BitXorAssign
        + Shl<Output = Self>
        + Shr<Output = Self>
        + ShlAssign
        + ShrAssign
        + fmt::Display
        + fmt::Debug
        + fmt::Binary
        + fmt::Octal
    {
        fn zero() -> Self;
        fn one() -> Self;
        fn min_value() -> Self;
        fn max_value() -> Self;
    }

    macro_rules! impl_integral {
        ($($ty:ty),*) => {
            $(
                impl Integral for $ty {
                    #[inline]
                    fn zero() -> Self {
                        0
                    }

                    #[inline]
                    fn one() -> Self {
                        1
                    }

                    #[inline]
                    fn min_value() -> Self {
                        Self::min_value()
                    }

                    #[inline]
                    fn max_value() -> Self {
                        Self::max_value()
                    }
                }
            )*
        };
    }

    impl_integral!(i8, i16, i32, i64, i128, isize, u8, u16, u32, u64, u128, usize);
}


Measured memory_bytes: 12028