#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <iomanip>
#include <cmath>
#include <functional>
using namespace std;
#define diff(x,y) ((x > y) ? (x - y) : (y - x))
#define us(x) (x > 0) ? x : x * -1
#define lli long long int
#define Black 'B'
#define White 'W'

int main() {
	int w, h;
	char c;
	bool bw;
	cin >> w >> h >> c;
	if (c == Black)	bw = false;
	else			bw = true;
	for (int i = 0; i < h; i++) {
		for (int j = 0; j < w; j++) {
			if (bw)	cout << White;
			else	cout << Black;
			bw = bw ? false : true;
		}
		if (w % 2 == 0)	bw = bw ? false : true;
		cout << endl;
	}

	return 0;
}