#include <algorithm>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <sstream>
#include <functional>
#include <map>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <list>
#include <numeric>
using namespace std;
const double PI = 3.14159265358979323846;
const double EPS = 1e-12;
const int INF = 1<<25;
typedef pair<int,int> P;
typedef long long ll;
typedef unsigned long long ull;
#define M 20
ll B, N, C[M];

int main(){
	cin>>B>>N;
	for(int i = 0; i < N; i++) cin>>C[i];
	sort(C, C+N);
	ll S = B;
	for(int i = 0; i < N; i++) S += C[i];
	ll res = S;
	C[N] = S/N;
	for(int i = 0; i <= N; i++){
		ll r = 0, b = B;
		for(int j = N-1; j >= 0; j--){
				r += abs(C[j]-C[i]);
				b += C[j]-C[i];
		}
		if(b<0) continue;
		res = min(res, r);
	}
	cout<<res<<endl;
	return 0;
}