#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())
#define endl "\n"

ll f(const vector<ll> &c, ll ave) {
    ll ans = 0;
    rrep(i, sz(c)) {
        ans += abs(ave - c[i]);
    }
    return ans;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    ll b, n;
    cin >> b >> n;
    vector<ll> c(n);
    rep(i, n) cin >> c[i];
    sort(all(c));
    ll sumc = accumulate(all(c), 0LL);
    ll low = 0, high = sumc / n;
    while((low + 2) < high) {
        ll lmid = (low * 2 + high) / 3;
        ll hmid = (low + high * 2) / 3;
        if (f(c, lmid) > f(c, hmid)) {
            low = lmid;
        }
        else {
            high = hmid;
        }
    }
    vector<ll> v;
    reps(i, low, high + 1) v.push_back(f(c, i));
    sort(all(v));
    cout << v[0] << endl;
    return 0;
}