#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>
#include<utility>
#include<stack>
#include<queue>
#include<list>
#include<bitset>

#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000

using namespace std;


int main(void) {
	bool flag;
	int w, h;
	char c;

	cin >> w >> h >> c;
	if (c == 'B') {
		flag = true;
	}
	else {
		flag = false;
	}
	FOR(i, 1, h) {
		if (flag == true) {
			FOR(t, 1, w) {
				if (t % 2 == 1) {
					cout << "B";
				}
				else {
					cout << "W";
				}
			}
		}
		else {
			FOR(t, 1, w) {
				if (t % 2 == 1) {
					cout << "W";
				}
				else {
					cout << "B";
				}
			}
		}
		cout << endl;
		if (flag == true) {
			flag = false;
		}
		else {
			flag = true;
		}
	}
	return 0;
}