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

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