#include <bits/stdc++.h>   #pragma GCC optimize( Ofast,inline,unroll-loops,fast-math )   #pragma GCC target( popcnt,abm,mmx,tune=native )   using namespace std;   long long n, i, j;   int main() {     [=]() {       ios_base ::sync_with_stdio(false);       cin.tie(nullptr);     }();     cin >> n;     for (; i < n; i++) {       for (j ^= j; j < n; j++) cout <<  WB [(i + j) % 2];       cout << endl;     }   }   