#include <iostream>		//cin, cout
#include <vector>		//vector
#include <algorithm>	//sort,min,max,count
#include <string>		//string,getline, to_string
#include <cstdlib>		//abs(int)
#include <utility>		//swap, pair
#include <deque>		//deque
#include <climits>		//INT_MAX
#include <bitset>		//bitset
#include <cmath>		//sqrt, ceil. M_PI, pow, sin
#include <ios>			//fixed
#include <iomanip>		//setprecision

using namespace std;

int main() {

	int W, H;
	char C;
	cin >> W >> H >> C;

	string S = "BW";

	bool flg;
	if (C == 'B') {
		flg = false;
	}
	else {
		flg = true;
	}

	for (int i = 0; i < H; i++) {
		for (int j = 0; j < W; j++) {
			cout << S[flg];
			flg = !flg;
		}
		cout << endl;
		if (W % 2 == 0) {
			flg = !flg;
		}
	}

	return 0;

}