https://www.acwing.com/problem/content/106/

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,a[100010],ans=0;
    cin>>n;
    for(int i=0;i<n;i++)cin>>a[i];
    sort(a,a+n);
    for(int i=0;i<n;i++)ans+=a[i]-a[i/2];
    cout<<ans;

    return 0;
}