Untitled

// clang-format off
#include <bits/stdc++.h>
using namespace std;

#define FIN(x) freopen(x, "r", stdin)
#define FASTIO ios_base::sync_with_stdio(0); cin.tie(0)
#define SZ(x) (sizeof(x) / sizeof(*x))
#define endl '\n'
typedef long long ll;

template <typename T> void print(T &v) {
  for (auto x : v)
    cout << x << ' ';
  cout << endl;
}
// clang-format on

int a[200000];

int main() {
  // FIN("input.txt");
  FASTIO;

  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++)
      cin >> a[i];

    int negCount = 0;
    int mi = INT_MAX;
    ll sum = 0;
    for (int i = 0; i < n; i++) {
      if (a[i] < 0)
        negCount++;

      mi = min(mi, abs(a[i]));
      sum += abs(a[i]);
    }

    if (negCount % 2 == 0) {
      cout << sum << endl;
    } else {
      cout << sum - 2 * mi << endl;
    }
  }

  return 0;
}