#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
	int n;
	cin >> n;
	vector<ll> a(n);
	for(auto &&v : a) cin >> v;
	sort(a.begin(), a.end());
	ll ans = 0;
	for(auto &&v : a) ans += abs(a[n / 2] - v);
	cout << ans << '\n';
}