#include <stdio.h>

void main(void){
	int w = 0 , h = 0;
	char selectChar = 'a';
	scanf("%d %d %c",&w,&h,&selectChar);
	int i = 1;
	while(i < w*h){
		printf("%c",selectChar);
		if(selectChar == 'B'){
			selectChar = 'W';
		}else if(selectChar == 'W'){
			selectChar = 'B';
		}
		if(i/w == 0){
			printf("\n");
		}
		i++;
	}
}