/*
    No.82 市松模様
    https://yukicoder.me/problems/no/82
*/
#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int w, h;
    char c;
    cin >> w >> h >> c;
    string mark;

    if (c == 'W')
        mark = "WB";
    else
        mark = "BW";

    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            cout << mark[(i + j) % 2];
        }
        cout << endl;
    }
}