#include <bits/stdc++.h>
using namespace std;
#define repl(i, l, r) for (ll i = (l); i < (r); i++)
#define rep(i, n) repl(i, 0, n)
#define CST(x) cout << fixed << setprecision(x)
using ll = long long;
const ll MOD = 1000000007;
const int inf = 1e9 + 10;
const ll INF = 4e18 + 10;
const int dx[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
const int dy[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
int main() {
	cin.tie(0);
	cout.tie(0);
	ios::sync_with_stdio(false);

	int w, h;
	char c;
	cin >> w >> h >> c;
	char a = 'B', b = 'W';
	if (c == 'B') swap(a, b);
	rep(i, h) {
		rep(j, w) cout << ((i + j) % 2 ? a : b);
		cout << endl;
	}

	return 0;
}