#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define llong long long

int main() {
    int n;
    cin >> n;
    vector<llong> y(n);
    rep(i, n) cin >> y[i];

    sort(y.begin(), y.end());
    llong base = y[n/2];
    llong result = 0;
    rep(i, n) result += abs(base - y[i]);
    cout << result << "\n";
}