use std::io::*;

fn f(a: &[i64], b: i64, x: i64) -> bool {
    let mut cnt1 = 0;
    let mut cnt2 = 0;
    for i in 0..a.len() {
        if a[i] > x {
            cnt1 += a[i] - x;
        } else {
            cnt2 += x - a[i];
        }
    }
    if cnt1 + b >= cnt2 {
        true
    } else {
        false
    }
}

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();

    let b: i64 = itr.next().unwrap().parse().unwrap();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let c: Vec<i64> = (0..n)
        .map(|_| itr.next().unwrap().parse().unwrap())
        .collect();

    let mut l = 0;
    let mut r = *c.iter().max().unwrap() + 1;
    for _ in 0..1000 {
        let mid = (l + r) >> 1;
        if f(&c, b, mid) {
            l = mid;
        } else {
            r = mid;
        }
    }

    let mut ans = 0;
    for i in 0..n {
        ans += (c[i] - l).abs();
    }
    println!("{}", ans);
}