#include <bits/stdc++.h>   using namespace std;   int main() {     int k;     scanf( %d , &k);     if (k % 2 == 1) {       printf( -1 n );       return 0;     }     char a[k][k];     memset(a, 0, sizeof(a));     for (int layer = 0; layer < k / 2; layer++) {       char c;       if (layer % 2)         c =  w ;       else         c =  b ;       for (int runner = layer; runner < k - layer; runner++)         a[runner][layer] = a[layer][runner] = a[runner][k - layer - 1] =             a[k - layer - 1][runner] = c;     }     for (int i = 0; i < k; i++)       for (int j = 0; j < k; j++) {         for (int l = 0; l < k; l++)           if (i % 2)             if (a[j][l] ==  w )               printf( b );             else               printf( w );           else             printf( %c , a[j][l]);         printf(  n );       }     return 0;   }   