#include <iostream>
using namespace std;

int main() {
    int w, h;
    char c;
    cin >> w >> h >> c;
    bool row, column = c == 'B';
    for (int i = 0; i < h; i++) {
        row = column;
        for (int j = 0; j < w; j++) {
            cout << (row ? 'B' : 'W');
            row = !row;
        }
        column = !column;
        cout << endl;
    }
    return 0;
}