use std::io::*;

fn f(a: &[f64], b: f64, x: f64) -> f64 {
    let mut cnt1 = 0.0;
    let mut cnt2 = 0.0;
    for i in 0..a.len() {
        if a[i] > x {
            cnt1 += a[i] - x;
        } else {
            cnt2 += x - a[i];
        }
    }
    if cnt1 + b >= cnt2 {
        cnt1 + cnt2
    } else {
        1e12
    }
}

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: f64 = itr.next().unwrap().parse().unwrap();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let c: Vec<f64> = (0..n)
        .map(|_| itr.next().unwrap().parse().unwrap())
        .collect();

    let mut l = 0.0;
    let mut r = 1e10;
    for _ in 0..1000 {
        let x1 = (l + l + r) / 3.0;
        let x2 = (l + r + r) / 3.0;
        let y1 = f(&c, b, x1);
        let y2 = f(&c, b, x2);
        if y1 > y2 {
            l = x1;
        } else {
            r = x2;
        }
    }
    println!("{}", f(&c, b, l.round()) as u64);
}