#include<iostream>
using namespace std;
int main(void)
{
	int j, i, p = 0, w, h;
	char k[1],s[2] = {'B','W'};

	cin >> w >> h >> k[0];
	if (k[0] == 'W')p++;
	for (j = 0; j < h; j++) {
		for (i = 0; i < w; i++) {
			cout << s[p % 2];
			p++;
		}
		cout << endl;
		if (w % 2 == 0)p++;
	}



	return 0;
}