#include <bits/stdc++.h>
using namespace std;

int main()
{
	int H, W;
	char C;
	cin >> W >> H >> C;

	char r = 'B';
	if( C == 'B' ) r = 'W';
	vector<string> ans( H, string( W, ' ' ) );
	for( int i = 0; i < H; i++ ) {
		for( int j = 0; j < W; j++ ) {
			if( (i + j) % 2 ) ans[i][j] = r;
			else ans[i][j] = C;
		}
	}

	for( int i = 0; i < H; i++ ) {
		cout << ans[i] << endl;
	}
}