#include <vector>
#include <string>
#include <algorithm>
#include <numeric>
#include <iostream>
#include <fstream>
#include <queue>
#include <cstring>
using namespace std;

using ll = long long;
using ull = unsigned long long;

using P = pair<ll,ll>;

int main()
{
  char gara[2] = {'B','W'};

  int w,h;
  char c;
  cin >> w >> h >> c;

  int index = 0;
  if(c == 'W')
    index = 1;

  int tmp_index = index^1;

  for(int y = 0; y < h; ++y)
  {
    for(int x = 0; x < w; ++x)
    {
      cout << gara[index];
      index ^= 1;
    }

    index = tmp_index;
    tmp_index = index^1;

    cout << endl;
  }
}