#include <stdio.h>
#include <algorithm>
#include <deque>
using namespace std;
using ll = long long;

//82
int main() {
	int w, h;
	char c, color[2];
	scanf("%d %d %c", &w, &h, &c);
	color[0] = c;
	color[1] = c != 'B' ? 'B' : 'W';

	for (int i = 0; i < h; i++) {
		for (int j = 0; j < w; j++)
			printf("%c", color[i + j & 1]);
		printf("\n");
	}
}