#include <iostream>

void solve() {
    int w, h;
    char c;
    std::cin >> w >> h >> c;
    int d = (c == 'W');

    for (int i = 0; i < h; ++i) {
        for (int j = 0; j < w; ++j) {
            int x = (i + j + d) % 2;
            std::cout << "BW"[x];
        }
        std::cout << std::endl;
    }
}

int main() {
    std::cin.tie(nullptr);
    std::cout.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}