// No.609 Noelちゃんと星々
// https://yukicoder.me/problems/no/609
//

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

long long int solve(vector<int> &stars, int N);
long long calc_score(int n, vector<int>& stars);


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

    unsigned int N;
    cin >> N;

    vector<int> stars(N);
    for (int i = 0; i < N; ++i)
        cin >> stars[i];

    long long ans = solve(stars, N);
    cout << ans << endl;
}

long long int solve(vector<int> &stars, int N) {
    sort(stars.begin(), stars.end());

    int median;
    if (N % 2 == 1)
        median = stars[N/2];
    else
        median = (stars[(N-1)/2] + stars[N/2]) / 2;

    long long ans = calc_score(median, stars);
    return ans;
}


long long calc_score(int n, vector<int>& stars) {
    long long ans = 0;
    for (auto s: stars) {
        ans += abs(s - n);
    }
    return ans;
}