#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string>
#include<iostream>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include <sstream>
#include<iomanip>
#include <ctype.h>
#include <fstream>
#include <cassert>
//#include <bits/stdc++.h>
using namespace std;

//#include<bits/stdc++.h>


	
int main() {
	long long int b;
	cin >> b;
	int n;
	cin >> n;
	long long int x[15] = {};
	long long int t = 0;
	for (int i = 0; i < n; i++) {
		cin >> x[i];
		t += x[i];
	}
	long long int w = t / n;
	long long int ans = 0;
	long long int h = 0;
	for (int i = 0; i < n; i++) {
		h += abs(x[i]-w);
	}
	ans = h;

	//cout << ans << endl;

	w = t / n-1;
	if (w >= 0) {
		h = 0;
		for (int i = 0; i < n; i++) {
			h += abs(x[i] - w);
		}
		ans = min(ans, h);
	}

	//cout << ans << endl;

	w = (t + b) / n;
	h = 0;
	for (int i = 0; i < n; i++) {
		h += abs(x[i] - w);
	}
	ans = min(ans, h);

	//cout << ans << endl;

	w = (t + b) / n - 1;
	if (w >= 0) {
		h = 0;
		for (int i = 0; i < n; i++) {
			h += abs(x[i] - w);
		}
		ans = min(ans, h);
	}
	cout << ans << endl;


	return 0;
}