#include <algorithm>
#include <climits>
#include <cstdlib>
#include <vector>
#include <cctype>
#include <deque>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <ctime>
#include <stack>
#include <cstdio>
#include <string>
#include <iomanip>
#include <cstring>
#include <iostream>
#include <functional>

using namespace std;

typedef long long ll;


#define LLMAX LLONG_MAX
#define IMAX INT_MAX


int main() {
  int w, h; char c;
  cin >> w >> h >> c;
  char p[] = {'B', 'W'};
  if (c == 'W') swap(p[0], p[1]);
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if ((i+j)%2 == 0) {
        cout << p[0];
      }else {
        cout << p[1];
      }
    }
    cout << endl;
  }
}