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

int main() {
	int n;
	cin >> n;
	vector<int> c(n);
	for (int i = 0; i < n; i++){
		cin >> c[i];
	}
	sort(c.begin(), c.end());
	long long a = 0, b = 0;
	for (int i = 0; i < n; i++){
		if (i % 2 == 0){
			a += c[i];
		}else{
			b += c[i];
		}
	}
	cout << abs(abs(a) - abs(b)) << endl;
}