#include <iostream>
using namespace std;
int w, h;
char c, a = 'W', b = 'B';

int main() {
  cin >> w >> h >> c;
  if (c == 'B') {
    a = 'B', b = 'W';
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if ((i + j) % 2) cout << b;
      else cout << a;
    }
    cout << endl;
  }
}