Problem:
Score : 600 points

Problem Statement

Snuke is standing on a two-dimensional plane. In one operation, he can move by 1 in the positive x-direction, or move by 1 in the positive y-direction.

Let us define a function f(r, c) as follows:

f(r,c) := (The number of paths from the point (0, 0) to the point (r, c) that Snuke can trace by repeating the operation above)

Given are integers r_1, r_2, c_1, and c_2.
Find the sum of f(i, j) over all pair of integers (i, j) such that r_1 ≤ i ≤ r_2 and c_1 ≤ j ≤ c_2, and compute this value modulo (10^9+7).

Constraints

1 ≤ r_1 ≤ r_2 ≤ 10^6

1 ≤ c_1 ≤ c_2 ≤ 10^6

All values in input are integers.

Input

Input is given from Standard Input in the following format:

r_1 c_1 r_2 c_2

Output

Print the sum of f(i, j) modulo (10^9+7).

Sample Input 1

1 1 2 2

Sample Output 1

14

For example, there are two paths from the point (0, 0) to the point (1, 1): (0,0) → (0,1) → (1,1) and (0,0) → (1,0) → (1,1), so f(1,1)=2.

Similarly, f(1,2)=3, f(2,1)=3, and f(2,2)=6. Thus, the sum is 14.

Sample Input 2

314 159 2653 589

Sample Output 2

602215194

Solution in Rust (1.15.1) (judge verdict: Time Limit Exceeded)

// This code is generated by [cargo-atcoder](https://github.com/tanakh/cargo-atcoder)
// Original source code:
/*
use proconio::input;
#[allow(unused_imports)]
use proconio::marker::*;
#[allow(unused_imports)]
use std::cmp::{max, min};
#[allow(unused_imports)]
use std::collections::*;
#[allow(unused_imports)]
use std::f64::consts::*;

#[allow(unused)]
const INF: usize = std::usize::MAX / 4;
#[allow(unused)]
const M: usize = 1000000007;

fn inv(a: usize) -> usize {
    let m = M as i64;
    let mut a = a as i64;
    let mut b = m as i64;
    let mut u = 1;
    let mut v = 0;
    let mut tmp;
    while b != 0 {
        let t = a / b;
        a -= t * b;
        tmp = a;
        a = b;
        b = tmp;
        u -= t * v;
        tmp = u;
        u = v;
        v = tmp;
    }
    u %= m;
    if u < 0 {
        u += m;
    }
    return u as usize;
}

fn f(r: usize, c: usize, fa: &Vec<usize>) -> usize {
    (fa[r + c] * inv(fa[r]) % M) * inv(fa[c]) % M
}

fn g(r: usize, c: usize, fa: &Vec<usize>) -> usize {
    let mut s = 0;
    for i in 0..=r {
        s = (s + f(i + 1, c, fa)) % M;
    }
    s
}

fn main() {
    input! {
        r1: usize,
        c1: usize,
        r2: usize,
        c2: usize,
    }
    let mut f = vec![1; r2 + c2 + 2];
    for i in 1..f.len() {
        f[i] = i * f[i - 1] % M;
    }
    let mut result = g(r2, c2, &f);
    result = (result + M - g(r2, c1 - 1, &f)) % M;
    result = (result + M - g(r1 - 1, c2, &f)) % M;
    result = (result + g(r1 - 1, c1 - 1, &f)) % M;
    println!("{}", result);
}
*/

fn main() {
    let exe = "/tmp/bin6F31F957";
    std::io::Write::write_all(&mut std::fs::File::create(exe).unwrap(), &decode(BIN)).unwrap();
    std::fs::set_permissions(exe, std::os::unix::fs::PermissionsExt::from_mode(0o755)).unwrap();
    std::process::exit(std::process::Command::new(exe).status().unwrap().code().unwrap())
}

fn decode(v: &str) -> Vec<u8> {
    let mut ret = vec![];
    let mut buf = 0;
    let mut tbl = vec![64; 256];
    for i in 0..64 { tbl[TBL[i] as usize] = i as u8; }
    for (i, c) in v.bytes().filter_map(|c| { let c = tbl[c as usize]; if c < 64 { Some(c) } else { None } }).enumerate() {
        match i % 4 {
            0 => buf = c << 2,
            1 => { ret.push(buf | c >> 4); buf = c << 4; }
            2 => { ret.push(buf | c >> 2); buf = c << 6; }
            3 => ret.push(buf | c),
            _ => unreachable!(),
        }
    }
    ret
}

const TBL: &'static [u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const BIN: &'static str = "<base64-encoded ELF executable removed>";