#include<stdio.h>

int main()
{
  char c;
  int i,j;
  int row;   //行
  int column;//列
  char a[2]={'W','B'};
  int k;

  scanf("%d %d %c",&column,&row,&c);


  if(c==a[0]){k = 0;}
  else{k = 1;}

  for(i=0;i<row;i++){
    for(j=0;j<column;j++){
      printf("%c",a[k]);
      k++;
      if(k==2){k=0;}
    }
    printf("\n");
  }

  return 0;
}