#ifndef LOCAL
#include <bits/stdc++.h>
#define debug(...)
#endif

using namespace std;
#define int long long
#define cinv(v) for (auto &it:v) cin>>it;
#define coutv(v) for (auto &it:v) cout<< it<<' '; cout<<'\n';

void shelby() {
    int n;
    cin >> n;
    multiset<int, greater<> > ms;
    for (int i = 1; i <= n; ++i) {
        int x;
        cin >> x;
        ms.insert(x);
    }
    int cnt = 0, ans = 0;
    while (!ms.empty()) {
        int x = *ms.begin();
        if (x < 0 && cnt >= 2) break;
        ans += (cnt % 2 ? -1 : 1) * x;
        ms.erase(ms.begin());
        cnt++;
        debug(ms, ans);
    }
    cout << ans << '\n';
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    int t = 1;
    cin >> t;
    for (int _ = 1; _ <= t; ++_) {
        // cout << "Case " << _ << ": ";
        shelby();
    }
}