func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int t, x = 0, k = 0;     cin >> t;     while (t--) {       int m, n, x, y = 0;       cin >> m;       cin >> n;       x = m * n;       int a[x];       for (int i = 0; i < x; i++) {         cin >> a[i];         if (a[i] < 0) {           a[i] = 0 - a[i];           k++;         }         y = y + a[i];       }       sort(a, a + x);       if (k % 2 == 0)         cout << y << endl;       else         cout << y - 2 * a[0] << endl;       k = 0;     }     return 0;   }   