#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  vector<Int> y(n);
  for(Int i=0;i<n;i++) cin>>y[i];
  sort(y.begin(),y.end());
  Int ans=0;
  for(Int i=0;i<n;i++) ans+=abs(y[i]-y[n/2]);
  cout<<ans<<endl;
  return 0;
}