#include <iostream>
using namespace std;
int main()
{
    int w,h;
    char c1,c2;
    cin>>w>>h>>c1;
    if(c1=='W'){
        c2='B';
    }else{
        c2='W';
    }
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            if(i%2==0){
                if(j%2==0)cout<<c1;
                if(j%2!=0)cout<<c2;
            }else{
                if(j%2!=0)cout<<c1;
                if(j%2==0)cout<<c2;
            }
        }
        cout<<endl;
    }
    return 0;
}