#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
using ll = long long;

int main() {
    int n; cin >> n;
    vector<ll> a(n);
    for (ll &ai: a) cin >> ai;
    sort(a.begin(), a.end());
    ll ans = 0;
    for (ll ai: a) ans += abs(ai - a[n / 2]);
    cout << ans << endl;
    return 0;
}