// 

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

using ll = long long;

#define rep(i, n) for (int i=0; i<(int)(n); ++(i))
#define rep3(i, m, n) for (int i=(m); (i)<(int)(n); ++(i))
#define repr(i, n) for (int i=(int)(n)-1; (i)>=0; --(i))
#define rep3r(i, m, n) for (int i=(int)(n)-1; (i)>=(int)(m); --(i))
#define all(x) (x).begin(), (x).end()

const int INF = (int)(1e9);

int main() {
    int n;
    cin >> n;
    vector<int> a(n);
    rep(i, n) cin >> a[i];
    sort(a.rbegin(), a.rend());
    ll x = 0, y = 0;
    int li = 0, ri = n-1;
    while (li <= ri) {
        if (li == (n-1)-ri) {
            x += a[li];
            ++li;
        }
        else {
            y += -a[ri];
            --ri;
        }
    }
    cout << (x-y) << endl;
    return 0;
}