#include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for(int(i)=0;(i)<(n);++(i))
int main(){
    int W,H;char C;cin>>W>>H>>C;
    REP(y,H){REP(x,W)cout<<"WB"[(y+x+(C=='B'))%2];cout<<endl;}
}