#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
 
#define MOD 1000000009
 
int main(){
  int w,h;
  char c;
  cin>>w>>h>>c;
  int flag = 0;
  char t[2]={'B','W'};
  if(c=='W')swap(t[0],t[1]);
  rep(y,0,h){
    rep(x,0,w){
      cout << t[(x+y)%2];
    }
    cout << endl;
  }
  return 0;
}