#include <bits/stdc++.h>
#include<iostream>
#include<iomanip>
#include<string>
#include<algorithm>
#include<vector>
#include<set>
#include<list>
#include<queue>
#include<math.h>
#include<bitset>
using ll = long long;
using namespace std;

ll solve(vector<int> &v, ll b, ll t1, ll t2 = -1){
    ll ret = 1e10;
    if (t2 == -1) t2 = t1;
    if (t1 > t2) swap(t1, t2);
    for (ll i = t1; i <= t2; i++){
        ll ans = 0;
        for (int j = 0; j < v.size(); j++){
            if (v[j] > i) {
                b += (v[j] - i);
                ans += (v[j] - i);
            }
        }
        for (int j = 0; j < v.size(); j++){
            if (v[j] < i) {
                if (b >= (i - v[j])) {
                    b -= (i - v[j]);
                    ans += (i - v[j]);
                }
            }
        }
        ret = min(ret, ans);
    }
    return ret;
}

int main(){
    ll b, n, t1, t2, ave = 0, ans = 0;
    cin >> b >> n;
    vector<int> v(n);
    for (int i = 0; i < n; i++) {
        cin >> v[i];
        ave += v[i];
    }
    ave /= n;
    sort(v.begin(), v.end());
    if (n%2) {
        t1 = v[n/2];
        if (ave < t1) t1 = ave;
        ans = solve(v, b, t1);
    } else {
        t2 = v[n/2];
        t1 = v[n/2 - 1];
        if (ave < t1) {
            t1 = ave;
            t2 = ave;
        }
        if (ave < t2) t2 = ave;
        ans = solve(v, b, t1, t2);
    }
    cout << ans << endl;
}