#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int w, h;
  char c;
  cin >> w >> h >> c;
  rep(i, h) {
    rep(j, w) {
      cout << (char) ((i + j) % 2 == 0 ? c : 'B' ^ 'W' ^ c);
    }
    cout << endl;
  }
  return 0;
}