func_code_string: #include <bits/stdc++.h>   using namespace std;   const int INF = 1e9 + 8;   const int mod = 1e9 + 7;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int t;     cin >> t;     while (t--) {       long long n, m;       cin >> n >> m;       long long arr[n][m];       long long x = 0;       for (long long i = 0; i < (n); i++) {         for (long long j = 0; j < (m); j++) {           cin >> arr[i][j];           if (arr[i][j] < 0) {             x++;           }         }       }       long long ans = 0;       long long minval = 101;       for (long long i = 0; i < (n); i++) {         for (long long j = 0; j < (m); j++) {           ans += abs(arr[i][j]);           minval = min(minval, abs(arr[i][j]));         }       }       if (x % 2 != 0) {         ans -= 2 * minval;       }       cout << ans << endl;     }   }   