#include <iostream>

using namespace std;

int main(int argc, const char* argv[])
{
	int W, H;
	char C;
	cin >> W >> H >> C;
	char _C = C == 'B' ? 'W' : 'B';
	for (int j = 0; j < H; j++) {
		for (int i = 0; i < W; i++) {
			cout << ((i + j) % 2 == 0 ? C : _C);
		}
		cout << endl;
	}
	return 0;
}