#include <iostream>

using namespace std;

int main() {
    int w, h;
    char c, ch[2];
    cin >> w >> h >> c;

    if (c < 'W') {
        ch[0] = 'B';
        ch[1] = 'W';
    } else {
        ch[0] = 'W';
        ch[1] = 'B';
    }

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


    return 0;
}