`\color{pink}{#Bơ}`

#include <bits/stdc++.h>
#define B 'B'
#define W 'W'
#define fast ios::sync_with_stdio(0); cin.tie(0);
using namespace std;

int main() {
    fast
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cout << (((i + j) % 2 == 0) ? B : W);
        }
        cout << '\n';
    }
    return 0;
}

`\color{#1AD5F7}{⋆⟡H}\color{#1AD5F7}{a}\color{#4DA6E6}{r}\color{#668EDD}{i}\color{#8077D5}{i}\color{#995FCD}{i}\color{#EA2F90}{⟡⋆}`