#include<stdio.h>
main(){
    int W,H;
    char c;
    scanf("%d %d %c",&W,&H,&c);
    char color[] = "BW";
    int bw = c=='B'?0:1;//bならば0
    printf("bw = %d\nc = %c\n",bw,c);//
    for(int i = 0;i < H;i++){
        for(int j = 0;j < W;j++){
            printf("%c",color[bw]);
            bw = !bw;
        }
        bw = !bw;//反転
        printf("\n");
    }
}