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

int main(void) {
	int W, H; char C;
	cin >> W >> H >> C;
	
	char nC = 'W';
	if(C == nC) nC = 'B';
	
	for(int i = 0; i < H; ++i) {
		for(int j = 0; j < W; ++j) {
			if((i + j) % 2 == 0) cout << C;
			else cout << nC;
		}
		
		cout << "\n";
	}
	
	return 0;
}