#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
typedef long long LL;

LL B, N;
LL C[10];
LL INF = 1e15;
LL calc(LL x){
  LL need = 0, res = 0;
  for(int i=0;i<N;++i){
	res += abs(x - C[i]);
	need += x - C[i];
  }
  
  if(B < need) return INF;
  return res;
}

int main(){
  cin >> B >> N;
  for(int i=0;i<N;++i) cin >> C[i];

  LL x1 = 0, x2 = 1000000001;
  while(x2-x1 > 3){
	LL a1 = (x1*2 + x2) / 3;
	LL a2 = (x1 + x2*2) / 3;
	LL y1 = calc(a1), y2 = calc(a2);
	if(y1 <= y2)
	  x2 = a2;
	else
	  x1 = a1;
  }

  LL ans = INF;
  for(int x=x1;x<=x2;++x)
	ans = min(ans, calc(x));
  cout << ans << endl;
  
  return 0;
}