#include<stdio.h>

int main(void){
	int w,h,cf=0,cg,i,j;
	char s[4];
	scanf("%d%d%s",&w,&h,s);
	if(s[0] == 'B'){cf = 1;}
	for(i = 1;i <= h;i++){
		cg = cf;
		for(j = 1;j <= w;j++){
			if(cg){printf("B");cg = 0;}else{printf("W");cg = 1;}
		}
		printf("\n");
		if(cf){cf = 0;}else{cf = 1;}
	}
	return 0;
}