#include "bits/stdc++.h"
using namespace std;

int main() {
	int W, H;
	char C;
	bool F[50];
	cin >> W >> H >> C;
	if (C == 'B') F[0] = true;
	else F[0] = false;
	for (int i = 1; i < H; i++) {
		F[i] = !F[i - 1];
	}
	for (int i = 0; i < H; i++) {
		for (int j = 0; j < W; j++) {
			if (F[i]) cout << 'B';
			else cout << 'W';
			F[i] = !F[i];
		}
		cout << endl;
	}
}