#include <iostream>
using namespace std;
int main() {
	char c[2] = { 'B','W' };
	int W, H;
	char C;
	int n,temp;
	cin >> W >> H >> C;
	if (C == 'B') { n = temp = 0; }
	else { n = temp = 1; }
	for (int i = 0; i < H; i++) {
		for (int j = 0; j < W;j++) {
			cout << c[n%2];
			n++;
		}
		cout << endl;
		n = ++temp;
	}
	return 0;
}