#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> Pr;

int w, h;
char c;

int main() {
	cin >> w >> h >> c;
	for (int i = 0; i < h; i++) {
		for (int j = 0; j < w; j++) {
			if (c == 'B') {
				if ((j % 2 == 0 && i % 2 == 0)||
					(j % 2 == 1 && i % 2 == 1))cout << c;
				else cout << "W";
			}
			else {
				if ((j % 2 == 0 && i % 2 == 0) ||
					(j % 2 == 1 && i % 2 == 1))cout << c;
				else cout << "B";
			}
		}
		cout << endl;
	}
	return 0;
}