#include <stdio.h>

int main(void)
{
  int weight, height, i, j, idx;
  char color[4];

  scanf("%d%d\n%c", &weight, &height, &color[0]);
  if(color[0] == 'B'){
    color[1] = 'W';
  }else if(color[0] == 'W'){
    color[1] = 'B';
  }
  for(i = 0; i < height; i++){
    for(j = 0; j < weight; j++){
      idx = (j + i) % 2;
      printf("%c", color[idx]);
    }
    puts("");
  }

  return 0;
}