//  Stick Lengths

#include<bits/stdc++.h>

using namespace std;
using ll = long long;

int main() {
    int n; cin >> n;
    vector<ll> in(n);
    for (auto &e: in) cin >> e;
    std::sort(in.begin(), in.end());
    ll target = in[n/2];
    ll target2 = in[n/2 + 1];
    ll count = 0, count2 = 0;
    for (auto e: in) {
        count += abs(target - e);
        count2 += abs(target2 - e);
    }
    cout << min(count, count2) << endl;


    return 0;
}