#include <bits/stdc++.h>
#define int long long
#define double long double
using namespace std;
const int MOD = 1000000007;
const int INF = 1e14;
using Graph = vector<vector<int>>;

signed main(){
  int W, H;
  cin >> W >> H;
  char A;
  cin >> A;
  char T;
  if( A == 'B' ) T = 'W';
  else T = 'B';
  for( int i = 0; i < H; i++ ){
    for( int j = 0; j < W; j++ ){
      if( i%2 == j%2 ) cout << A;
      else cout << T;
    }
    cout << endl;
  }
}