#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
const int N = 100010;
int n,a[N],sum;
int main(){
scanf("%d",&n);
for(int i = 1;i<=n;i++){
scanf("%d",&a[i]);
}
sort(a+1,a+n+1);
int x = 0;
x = n/2+1;
for(int i=1;i<=n;i++){
sum += abs(a[x] - a[i]);
}
printf("%d",sum);
return 0;
}