#include<bits/stdc++.h>
using namespace std;
#define int long long

#ifdef LOCAL_DEBUG
  #include "LOCAL_DEBUG.hpp"
#endif

signed main(){

  int b,n; cin >> b >> n;
  vector<int> a(n);
  bool check = true;
  for(int i = 0; i < n; i++){
    cin >> a[i];
    if(i > 0 && a[i-1] != a[i]) check = false;
  }
  if(check){
    cout << 0 << endl;
    return 0;
  }

  auto f = [&](int t){
    int cnt = 0;
    for(int i = 0; i < n; i++){
      cnt += abs(t - a[i]);
    }
    return cnt;
  };

  int left = 0,right = 1 << 30;
  //[left , t1 , t2 , right]
  for(int i = 0; i < 100; i++){
    int t1 = (left * 2 + right) / 3;
    int t2 = (left + right * 2) / 3;
    t2 += 1;

    if(f(t1) > f(t2)) left = t1;
    else right = t2;
  }

  int ans = 1 << 30;
  for(int i = left; i <= right; i++){
    ans = min(ans,f(i));
    if(ans == 0){
      cout << i << endl;
      return 0;
    }
  }
  cout << ans << endl;

  return 0;
}