#include"bits/stdc++.h"
//#include<boost/multi_array.hpp>
//#include<boost/optional.hpp>
//#include<boost/range/irange.hpp>
//#include<boost/range/algorithm.hpp>
//#include<boost/range/adaptors.hpp>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<int, int>;
#define rep(i,n) for(int i=0; i<(n); i++)
#define rep2(i,x,n) for(int i=x; i<(n); i++)
#define all(n) begin(n),end(n)
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
const long long INF = numeric_limits<long long>::max();

void Main() {
	int w, h;
	char c;
	cin >> w >> h >> c;
	bool white;
	if (c == 'B') {
		white = false;
	} else {
		white = true;
	}
	rep(i, h) {
		bool black = white;
		rep(j, w) {
			if (white == true) {
				cout << 'W';
				white = false;
			} else {
				cout << 'B';
				white = true;
			}
		}
		white = !black;
		cout << endl;
	}
}

int main() {
	std::cin.tie(nullptr);
	std::ios_base::sync_with_stdio(false);
	std::cout << std::fixed << std::setprecision(15);
	Main();
	return 0;
}