func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     char board[n][n];     bool even = true;     for (int i = 0; i < n; i++)       for (int j = 0; j < n; j++) cin >> board[i][j];     for (int i = 0; i < n; i++) {       int c = 0;       for (int j = 0; j < n; j++) {         if (i - 1 >= 0 and board[i - 1][j] ==  o ) c++;         if (i + 1 < n and board[i + 1][j] ==  o ) c++;         if (j - 1 >= 0 and board[i][j - 1] ==  o ) c++;         if (j + 1 < n and board[i][j + 1] ==  o ) c++;         if (c % 2 == 1) even = false;       }     }     if (even)       cout <<  YES  << endl;     else       cout <<  NO  << endl;     return 0;   }   