#include <bits/stdc++.h>
using namespace std;

int main(){
  int w,h;
  char c;
  cin>>w>>h>>c;
  int flag=1;
  if(c=='W') flag*=-1;
  for(int i=0;i<h;i++){
    for(int j=0;j<w;j++){
      if(flag==1){
        cout<<"B";
      }
      else{
        cout<<"W";
      }
      flag*=-1;
    }
    cout<<endl;
    if(w%2==0) flag*=-1;
  } 
  return 0;
}