#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000
#define int long long
int C[10];
int N;
int check(int a) {
	int sum = 0;
	rep(i, N) sum += abs(C[i] - a);
	return sum;
}

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int B;
	cin >> B >> N;
	rep(i, N) cin >> C[i];
	int sum = 0;
	sort(C, C + N);
	int ans1 = C[(N - 1) / 2];
	int ans2 = C[N / 2];
	
	rep(i, N) sum += C[i];
	if (ans2 * N - sum > B) {
		//cout << ans2 * N - sum << " " << B << endl;
		cout << check((ans2 - (ans2 *  N - sum - B + N - 1) / N)) << endl;
	}
	else {
		cout << min(check(ans1), check(ans2)) << endl;
	}
	

    return 0;
}