#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
using namespace std;
typedef pair<int, int> pii;
#define rep(i,x) for(int i=0;i<(int)(x);i++)

int main(){
	bool bf = false, tmp = false;
	int w, h;
	char c;
	cin >> w >> h >> c;
	if (c=='B') bf = true;
	rep(i,h) {
		tmp = bf;
		rep(j,w) {
			if (tmp) cout << "B";
			else cout << "W";
			tmp = !tmp;
		}
		bf = !bf;
		cout << endl;
	}
	return 0;
}