#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <string>
#include <queue>
#include <map>
#include <stack>
#include <functional>
#include <complex>
#include <cmath>
#include <ccomplex>
using namespace std;

int main() {
	int w, h;
	char c[2];
	cin >> w >> h >> c[0];

	if (c[0] == 'B')c[1] = 'W';
	else c[1] = 'B';
	for (int i = 0; i < h; i++) {
		for (int j = 0; j < w; j++) {
			cout << c[(i + j) % 2];
		}
		cout << endl;
	}
}