#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define llong long long

llong getval(llong avgval, vector<llong> &c) {
    llong result = 0;
    for(int i: c) result += abs(avgval - i);
    return result;
}

int main() {
    int b, n;
    cin >> b >> n;
    vector<llong> c(n);
    rep(i, n) cin >> c[i];

    llong summary = accumulate(c.begin(), c.end(), 0);
    llong maxval = (summary+b) / n;
    llong minval = summary / n;
    
    llong result = LLONG_MAX;
    for(llong i=minval; i<=maxval; i++) {
        llong val = getval(i, c);
        if(result > val) result = val;
        else break;
    }

    cout << result << "\n";
}