#include <bits/stdc++.h>

using namespace std;

int main() {
  int w, h;
  char c;
  cin >> w >> h >> c;
  int color = c == 'B'? -1: 1;
  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      int cur = j % 2 == 0? color: -color;
      if (cur < 0) {
	cout << 'B';
      } else {
	cout << 'W';
      }
    }
    color *= -1;
    puts("");
  }
  return 0;
}