#include <bits/stdc++.h>
#ifdef LOCAL_DEBUG
#include "debug.h"
#else
#define dbg(...) (void)0
#endif
using u32 = unsigned int;
using i64 = long long;

namespace skadi {

void solve() {
    int n;
    std::cin >> n;
    std::vector<i64> a(n);
    bool neg = false, pos = false, zero = false;
    for (int i = 0; i < n; i++) {
        std::cin >> a[i];
        if (a[i] < 0) {
            neg = true;
        } else if (a[i] > 0) {
            pos = true;
        } else {
            zero = true;
        }
        a[i] = std::abs(a[i]);
    }
    if (n == 1) {
        std::cout << a[0] << '\n';
        return;
    }
    i64 sum = std::accumulate(a.begin(), a.end(), 0LL);
    if ((neg && pos) || zero) {
        std::cout << sum << '\n';
    } else {
        std::cout << sum - 2 * *std::min_element(a.begin(), a.end()) << '\n';
    }
}

} // namespace skadi

int main() {
#ifndef LOCAL_DEBUG
    std::cin.tie(nullptr)->sync_with_stdio(false);
#endif
    int t = 1;
    std::cin >> t;
    while (t--) {
        skadi::solve();
    }
    return 0;
}