#include<iostream>
#include<fstream>
#include<sstream>
#include<string>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<vector>
#include<list>
#include<algorithm>
#include<utility>
#include<complex>

using namespace std;
#define LL long long

LL B, N, C[10];
LL Csum[10];



int main(void){
	LL res = 10000000000LL;
	cin >> B >> N;
	for (int i = 0; i < N; i++){
		cin >> C[i];
		Csum[i] = C[i];
	}

	sort(C,C+N);
	sort(Csum, Csum + N);
	for (int i = 1; i < N; i++)Csum[i] += Csum[i - 1];
	for (int i = 0; i < N; i++){
		LL m = i + 1;
		LL n = N - m;
		LL x;
		if (C[i] * N > Csum[N - 1] + B)continue;
		if (m - n >= 0)x = C[i];
		else x = min(C[i + 1] - 1, (Csum[N - 1] + B)/N);


		res = min(res, (m - n)*x - (Csum[i]) + (Csum[N - 1] - Csum[i]));
	}

	cout << res << endl;

	return(0);
}