#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <algorithm>
#include <set>
#include <map>
#include <bitset>
#include <cmath>
#include <functional>
#include <iomanip>
#define vll vector<ll>
#define vvvl vector<vvl>
#define vvl vector<vector<ll>>
#define VV(a, b, c, d) vector<vector<d>>(a, vector<d>(b, c))
#define VVV(a, b, c, d) vector<vvl>(a, vvl(b, vll (c, d)));
#define re(c, b) for(ll c=0;c<b;c++)
#define all(obj) (obj).begin(), (obj).end()
typedef long long int ll;
typedef long double ld;
using namespace std;

int main(int argc, char const *argv[]) {
  ll h, w;std::cin >> w >> h;
  char c;std::cin >> c;
  if(c=='B'){
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
        std::cout << ((i+j)%2?'W':'B');
      }
      std::cout << '\n';
    }
  }else{
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
        std::cout << ((i+j)%2?'B':'W');
      }
      std::cout << '\n';
    }
  }

}