#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stdio.h>
#include <cstring>
#include <queue>
#include <stack>
#include <functional>
#include <math.h>
#include <iomanip>
using namespace std;
#define Would
#define you
const int INF = 999999999;
const int MOD = 1e9 + 7;
const double pi = 3.141592653589793238;

int main() {
	int a, b;
	char c, d;
	cin >> a >> b >> c;
	if (c == 'B') { d = 'W'; }
	else { d = 'B'; }
	for (int i = 0; i < b; ++i) {
		for (int j = 0; j < a; ++j) {
			if ((i + j) % 2 == 0) { cout << c; }
			else { cout << d; }
		}
		cout << endl;
	}
}