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

int main() {
  int n; cin >> n;
  vector<int> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a.begin(), a.end());
  ll y = 0, x = 0;
  for (int i = 0; i < n / 2; i++) {
    y += -a[i];
  }
  for (int i = n / 2; i < n; i++) {
    x += a[i];
  }
  cout << x - y << endl;
}