#include<iostream>
#include<algorithm>
#include<string>
#include<vector>
#include<set>
using namespace std;

void solve198()
{
	long long B, N;
	cin >> B >> N;
	long long ans = 0;
	vector<long long > BOX(N);

	long long val = 0;
	for (int i = 0; i < N; i++)
	{
		cin >> BOX[i];
		val += BOX[i];
	}

	val = val / N;
	vector<pair<long long,int>> goal(N);
	for (int i = 0; i < N; i++)
	{
		goal[i] = make_pair(abs(BOX[i] - val),i);
	}

	sort(BOX.begin(), BOX.end());
	reverse(BOX.begin(), BOX.end());
	
	sort(goal.begin(), goal.end());
	for (int i = 0; i < N; i++)
	{
		val = BOX[goal[i].second];
		for (int i = 0; i < N; i++)
		{
			if (BOX[i]>val){
				B += BOX[i] - val;
				ans += BOX[i] - val;
			}
			else if (BOX[i] < val){
				B += val - BOX[i];
				ans += val-BOX[i];
			}

		}
		if (B >= 0){
			cout << ans << endl;
		
			return;
		}
	}
	return;
}
int main(){
	solve198();
	return 0;
}