Untitled

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

void solve() {
	int n;
	cin >> n;
	vector<int> a(n);
	for (int& u : a) cin >> u;

	int num_neg = count_if(a.begin(), a.end(), [](int x) { return x < 0; });

	for (int& u : a) u = abs(u);

	int min_abs = *min_element(a.begin(), a.end());
	ll sum = accumulate(a.begin(), a.end(), 0LL);

	cout << (num_neg % 2 == 0 ? sum : sum - 2LL * min_abs) << '\n';
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	int tt;
	cin >> tt;
	while (tt--) {
		solve();
	}
}