func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long INF = 1e18;   const long long mod = 1e9 + 7;   const long long modd = 1;   const long long N = 1e5 + 5;   void solve() {     long long n, m;     cin >> n >> m;     long long a[n + 1][m + 1];     for (long long i = 0; i < n; i++)       for (long long j = 0; j < m; j++) cin >> a[i][j];     for (long long i = 0; i < n; i++) a[i][m] = a[i][m - 1] + 1;     for (long long i = 0; i < m; i++) a[n][i] = a[n - 1][i] + 1;     long long ans = 0;     for (long long i = n - 1; i >= 0; i = i - 1) {       for (long long j = m - 1; j >= 0; j = j - 1) {         if (a[i][j] == 0) a[i][j] = min(a[i + 1][j], a[i][j + 1]) - 1;         if (a[i][j] >= a[i + 1][j] || a[i][j] >= a[i][j + 1]) {           cout << -1;           return;         }         ans = ans + a[i][j];       }     }     cout << ans;   }   int32_t main() {     std::ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);     long long t = 1;     for (long long i = 1; i <= t; i = i + 1) {       solve();       cout << endl;     }   }   