#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(long long)b;i++)
#define rep(i,n) REP(i,0,n)

int d[10] = {6, 2, 5, 5, 4, 5, 6, 3, 7, 6};

int main() {
  
  int W, H, C; char c; cin >> W >> H >> c;
  if(c == 'B') C = 0; else C = 1;
  rep(i, H){
    rep(j, W) cout << ((C+i+j)&1 ? 'W' : 'B');
    cout << endl;
  }
  
  
  return 0;
}