#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<ll> vll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<vector<ll>> vvll;
const ll inf = 1e16;
const ll md = 1000000007;

int main() {
  int b,n;
  vi cc;
  cin>>b>>n;
  ll s=0LL;
  rep(_,n){
    int c;
    cin>>c;
    cc.push_back(c);
    s+=c;
  }
  s/=n;
  ll ans=0LL;
  for(int c:cc){
    ans+=abs(c-s);
  }
  cout<<ans<<endl;
  return 0;
}