#include <stdio.h>

int main(){
    int width, height;
    int i, j;
    char color;
    char BW[3] = "BW";

    scanf("%d %d %c", &width, &height, &color);

    for(i = 0; i < height; i++){
        for(j = 0; j < width; j++){
            if(color == 'B'){
                printf("%c", BW[(j + i)%2]);
            }else if(color == 'W'){
                printf("%c", BW[(j + i + 1)%2]);
            }
        }
        printf("\n");
    }
    return 0;
}