#include <bits/stdc++.h>

using namespace std;

int main() {
    int w, h;
    char c;
    cin >> w >> h >> c;

    char a = 'W', b = 'B';
    if (c == 'B') swap(a, b);
    
    for (int i = 0; i < h; ++i) {
        for (int j = 0; j < w; ++j) {
            cout << (((i + j) % 2 == 0) ? a : b);
        }
        cout << endl;
    }
    return 0;
}