#include <algorithm>
#include <vector>
#include <cfloat>
#include <string>
#include <cmath>
#include <set>
#include <cstdlib>
#include <map>
#include <ctime>
#include <iomanip>
#include <functional>
#include <deque>
#include <iostream>
#include <cstring>
#include <queue>
#include <cstdio>
#include <stack>
#include <climits>
#include <cctype>

using namespace std;

typedef long long ll;

int main() {
	ll b;
	cin >> b;
	ll n;
	cin >> n;
	ll sum = 0;
	ll c[10], maxv = 0;
	for (int i = 0; i < n; i++) {
		cin >> c[i];
		sum += c[i];
		maxv = max(maxv, c[i]);
	}
	ll ans = 1000000000;
	for (int i = -n; i <= n; i++) {
		ll t1 = 0, t2 = 0;
		for (int j = 0; j < n; j++) {
			t1 += abs(c[j] - (sum / n+i));
			t2 += sum / n + i;
		}
		if (t2 < 0 || t2 > sum + b) {
			continue;
		}
		ans = min(ans, t1);
	}
	for (int i = -n; i < n; i++) {
		ll v = min((sum + b) / n + n, maxv);
		ll t1 = 0, t2 = 0;
		for (int j = 0; j < n; j++) {
			t1 += abs(c[j] - (v + i));
			t2 += v + i;
		}
		if (t2 < 0 || t2 > sum + b) {
			continue;
		}
		ans = min(ans, t1);
	}
	cout << ans << endl;
}