#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <math.h>

using ll = long long;
using namespace std;

const int MOD = 1e9+7;

int main() {
    int N;
    cin >> N;
    vector<int> Y(N);
    for(int i = 0; i < N; i++)
    {
        cin >> Y[i];
    }
    sort(Y.begin(), Y.end());
    ll p = (Y[(N-1)/2] + Y[N/2]) / 2;
    ll ans = 0;
    for(int i = 0; i < N; i++)
    {
        ans += abs(Y[i] - p);
    }
    cout << ans << endl;
    return 0;
}