#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <vector>

using namespace std;

const int N = 100010;

int a[N],n;

int main(){
    cin >> n;
    for(int i = 1; i <= n; i++)
        cin >> a[i];
    sort(a + 1, a + n + 1);
    int pos;
    int ans = 0;
    if(n & 1){
        pos = a[(n + 1) / 2];
    }
    else pos = (a[n / 2] + a[n /2 + 1]) / 2;
    for(int i = 1; i <= n; i++){
        ans += abs(a[i] - pos);
    }
    cout << ans << endl;
}