#include "bits/stdc++.h"
#define _CRT_SECURE_NO_WARNINGS
#define rep(i,n) for(int i = 0;i < n;i++)
#define REP(i,n,k) for(int i = n;i < k;i++)
#define P(p) cout << (p) << endl;
#define sP(p) cout << setprecision(15) << fixed << p << endl;
#define vi vector<int>
#define mp(a,b) make_pair(a,b)
using namespace std;typedef long long ll;typedef unsigned long long ull;int dx[] = { 1, -1 , 0 , 0};int dy[] = { 0,  0,  1, -1};

void solve() {
  int b,n;
  cin >> b >> n;
  vi c(n);
  rep(i,n)cin >> c[i];
  ll left = 0,right = 1e15;
  while(right-left>2){
    ll l = (2*left + right)/3;
    ll r = (left + 2*right)/3;
    ll sl = 0,sr = 0,sbl = 0,sbr = 0;
    rep(i,n){
      sl += l-c[i];
      sr += r-c[i];
      sbl += abs(l-c[i]);
      sbr += abs(r-c[i]);
    }
    if(sl > b){
      right = l;
    }else if(sr > b){
      right = r;
    }else if(sbl >= sbr){
      left = l;
    }else{
      right = r;
    }
  }
  ll sum = 0;
  rep(i,n){
    sum += abs((left+right)/2 - c[i]);
  }
  P(sum);
}

int main() {
	solve();
	return 0;
}