#include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

	int W, H;
	char c, C;
	cin >> W >> H >> c;

	C = c;
	for (int i = 0; i < H; i++) {
		if (i >= 1 && c == 'B') {
			c = 'W';
		}
		else if(i >= 1){
			c = 'B';
		}
		C = c;
		for (int j = 0; j < W; j++) {
			if (C == 'B') {
				cout << 'B';
				C = W;
			}
			else {
				cout << 'W';
				C = 'B';
			}
		}
		cout << endl;
			
	}


	return 0;
}