#include <stdio.h>
int main(void){
    int w, h;
    int i, j;
    char c;
    scanf( "%d %d %c", &w, &h, &c );
    for( i = 0; i < h; i++ ){
        for( j = 0; j < w; j++ ){
            printf( "%c", c );
            c = ( c == 'B' ) ? 'W' : 'B';
        }
        printf( "\n" );
    }
}