#include<iostream>
#include<algorithm>
using namespace std;
int n,shop[100005],cnt;
int main(){
cin >> n;
for(int i = 1;i <= n;i++){
cin >> shop[i];
}
sort(shop+1,shop+1+n);
int ck = n/2+1;
for(int i = 1;i <= n;i++){
if(shop[i] > shop[ck]){
cnt += shop[i]-shop[ck];
}else{
cnt += shop[ck]-shop[i];
}
}
cout << cnt;
return 0;
}