func_code_string: #include <bits/stdc++.h>   using namespace std;   #pragma comment(linker,  /STACK:8000000 )   int main() {     int n;     scanf( %d , &n);     if (n % 2 == 1) {       printf( -1 );       return 0;     }     for (int k = 0; k != n; ++k)       for (int i = 0; i != n; ++i) {         for (int j = 0; j != n; ++j)           if ((j % 4 < 2) ^ (k % 2 == 0) ^ (i % 4 < 2))             printf( b );           else             printf( w );         printf(  n );       }     return 0;   }   