func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, m;     cin >> n >> m;     int a[n + 2][m + 2];     int counter = 1;     for (int i = 1; i <= n; i += 2) {       for (int j = 1; j <= m; j++) {         if (n % 2 && i == n && j % 2 == 1) continue;         a[i + (j % 2 == 1)][j] = counter;         counter++;       }     }     for (int i = 1; i <= n; i += 2) {       for (int j = 1; j <= m; j++) {         if (n % 2 && i == n && j % 2 == 0) continue;         a[i + (j % 2 == 0)][j] = counter;         counter++;       }     }     bool res = true;     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         if ((i < n && abs(a[i][j] - a[i + 1][j]) <= 1) ||             (j < m && abs(a[i][j] - a[i][j + 1]) <= 1))           res = false;       }     }     if (res) {       for (int i = 1; i <= n; i++) {         for (int j = 1; j <= m; j++) {           cout << a[i][j] <<    ;         }         cout <<   n ;       }     } else {       cout << -1;     }   }   