#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;


int main(){
  int W, H;
  char C1='W', C2='B';

  cin >> W >> H >> C1;
  if(C1=='B') C2='W';

  rep(i,H){
    rep(j,W){
      if((i+j)%2==0) cout << C1;
      else cout << C2;
    }
    cout << endl;
  }
  
  return 0;
}