func_code_string: #include <bits/stdc++.h>   using namespace std;   int c[3];   void solve() {     int m, n;     cin >> m >> n;     vector<vector<int>> matrix(m, vector<int>(n));     for (int i = 0; i < m; i++) {       for (int j = 0; j < n; j++) {         cin >> matrix[i][j];       }     }     for (int i = m - 1; i >= 0; --i) {       for (int j = n - 1; j >= 0; --j) {         if (matrix[i][j] != 0) {           continue;         } else {           int check;           check = matrix[i][j + 1] - 1;           if (check >= matrix[i + 1][j]) check = matrix[i + 1][j] - 1;           matrix[i][j] = check;         }       }     }     for (int i = m - 1; i >= 0; --i) {       for (int j = n - 1; j >= 0; --j) {         if (i != 0 && j != 0) {           if ((matrix[i][j] <= matrix[i][j - 1]) ||               (matrix[i][j] <= matrix[i - 1][j])) {             cout <<  -1  << endl;             return;           }         }       }     }     int sum = 0;     for (int i = 0; i < m; i++) {       for (int j = 0; j < n; j++) {         sum += matrix[i][j];       }     }     cout << sum << endl;     return;   }   int main() {     solve();     return 0;   }   