#[allow(unused_macros)]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        let mut next = || { iter.next().unwrap() };
        input_inner!{next, $($r)*}
    };
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes
                .by_ref()
                .map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

#[allow(unused_macros)]
macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr, ) => {};

    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };

    ($next:expr, mut $var:ident : $t:tt $($r:tt)*) => {
        let mut $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

#[allow(unused_macros)]
macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => {
        ( $(read_value!($next, $t)),* )
    };

    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };

    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };

    ($next:expr, bytes) => {
        read_value!($next, String).into_bytes()
    };

    ($next:expr, usize1) => {
        read_value!($next, usize) - 1
    };

    ($next:expr, $t:ty) => {
        $next().parse::<$t>().expect("Parse error")
    };
}

#[allow(unused_imports)]
use std::cmp::{max, min};
#[allow(unused_imports)]
use std::collections::{BinaryHeap, HashMap};

#[allow(dead_code)]
type Graph = Vec<Vec<usize>>;

fn main() {
    input! {
        n: usize,
        k: usize,
        mut sushi: [(usize, usize); n],
    }

    sushi.sort_by_key(|a| -(a.1 as i64));
    let mut neta = vec![0; n + 1];

    let mut index = 0;
    let mut score = 0;
    let mut kind = 0;
    let mut heap = BinaryHeap::new();

    while index < sushi.len() && index < k {
        let s = sushi[index];
        if neta[s.0] == 0 {
            score = score - (kind * kind) + (kind + 1) * (kind + 1);
            kind += 1;
        }
        neta[s.0] += 1;
        score += s.1;
        heap.push((-(s.1 as i64), s.0));
        // println!("{}, {}", index, score);
        index += 1;
    }

    let mut ans = score;

    while index < sushi.len() && !heap.is_empty() {
        let s = sushi[index];
        if neta[s.0] == 0 {
            while !heap.is_empty() {
                let s2 = heap.pop().unwrap();
                if neta[s2.1] > 1 {
                    neta[s2.1] -= 1;
                    neta[s.0] += 1;
                    score = score - (kind * kind) + (kind + 1) * (kind + 1) - (s2.0.abs() as usize)
                        + s.1;
                    // println!("{}, {}, {}", s2.0, s2.1, score);
                    kind += 1;
                    ans = max(score, ans);
                    break;
                }
            }
        }
        index += 1;
    }
    println!("{}", ans);
}


Measured memory_bytes: 10492