#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>

using namespace std;

int main() {
	int b, n;

	cin >> b >> n;
	vector<int> c(n, 0);
	long long total = 0;
	for (int i = 0; i < n; i++) {
		cin >> c[i];
		total += c[i];
	}

	long long ans = 1e18, tmp;
	int avg = total / n;
	for (int i = avg - 1; i <= avg + 1; i++) {
		if (i < 0) {
			continue;
		}

		if (i * n > total + b) {
			continue;
		}

		tmp = 0;
		for (int j = 0; j < n; j++) {
			tmp += abs(c[j] - i);
		}
		ans = min(ans, tmp);
	}
	cout << ans << endl;
	return 0;
}