#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define Would
#define you
#define please


int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


	int W, H;
	cin >> W >> H;
	char C;
	cin >> C;
	int A = 0;
	if (C == 'W') A++;

	rep(i, H) {
		rep(i, W) {
			if ((A + i) % 2) cout << 'W';
			else cout << 'B';
		}
		A++;
		cout << endl;
	}

	Would you please return 0;
}