#include <iostream>

using namespace std;

int main()
{

	int W, H;
	char C;
	cin >> W >> H >> C;

	char notC;
	notC =(  C == 'B' ? 'W' : 'B' );

	for( int y = 0; y < H; y++ ) {
		for( int x = 0; x < W; x++ ) {
			//cout << ( ( x + y )%2 ) << " c " << endl;
			cout << ( ( ( x + y )%2 == 0 )  ? C : notC );
		}
		cout << endl;
	}
	return 0;
}