#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
using ll = std::int64_t;

int main() {
    int n;
    std::cin >> n;
    std::vector<ll> c(n);
    for (ll &e : c) std::cin >> e;
    ll sum = std::accumulate(std::begin(c), std::end(c), 0ll);
    if (sum < 0) {
        for (auto &e : c) e *= -1;
    }
    std::sort(std::rbegin(c), std::rend(c));
    ll av = 0, bv = 0;
    for (int i = 0; i < n; i++) {
        (i & 1 ? bv : av) += c[i];
    }
    std::cout << std::abs(av) - std::abs(bv) << std::endl;
    return 0;
}