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

struct uns_t {} uns;
template <typename Element, typename Head, typename ...Args>
auto vec(Element init, Head arg, Args ...args) {
    if constexpr (sizeof...(Args) == 0) return std::vector(arg, init);
    else return std::vector(arg, vec(init, args...));
}
template <typename Element, typename Head, typename ...Args>
auto vec(uns_t, Head arg, Args ...args) {
    return vec(Element(), arg, args...);
}

int main() {
    int n; cin >> n;
    auto c = vec<int>(uns, n);
    for (auto &e : c) cin >> e;
    sort(begin(c), end(c));

    auto solver = [&](int ap, int bp) {
        deque<int> que(begin(c), end(c));

        int64_t a = 0, b = 0;
        bool turn = true;
        while (!que.empty()) {
            if (turn) {
                if (ap < 0) {
                    a += que.front();
                    que.pop_front();
                }
                if (ap > 0) {
                    a += que.back();
                    que.pop_back();
                }
            }
            else {
                if (bp < 0) {
                    b += que.front();
                    que.pop_front();
                }
                if (bp > 0) {
                    b += que.back();
                    que.pop_back();
                }
            }

            turn = !turn;
        }

        return abs(a) - abs(b);
    };

    auto m = -accumulate(begin(c), lower_bound(begin(c), end(c), 0), int64_t(0));
    auto p = +accumulate(lower_bound(begin(c), end(c), 0), end(c), int64_t(0));

    if (m < p) {
        cout << solver(1, 1) << endl;
    }
    else {
        cout << solver(-1, -1) << endl;
    }
}