#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;

    vector<int> y(n);
    for (int i = 0; i < n; i++) {
        cin >> y[i];
    }

    int m = n / 2;
    nth_element(y.begin(), y.begin() + m, y.end());

    int x = y[m];

    int64_t r = 0;
    for (int i = 0; i < n; i++) {
        r += abs(y[i] - x);
    }

    cout << r << endl;

    return 0;
}