#include <bits/stdc++.h>
#include <iostream>
#include <string>
using namespace std;

int main() {
	int w, h;
	char c, n, m;
	bool flg = 1;
	cin >> w >> h >> c;
	if (c == 'B') {
		n = 'B';
		m = 'W';
	} else {
		n = 'W';
		m = 'B';
	}
	for (int i = 0; i < h; ++i) {
		for (int j = 0; j < w; ++j) {
			if (flg == 1) {
				cout << n;
				flg = 0;
			} else {
				cout << m;
				flg = 1;
			}
		}
		if (w % 2 == 0) {
			if (flg == 1) {
				flg = 0;
			} else {
				flg = 1;
			}
		}
		cout << endl;
	}

}

#950832