#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using PII = std::pair<int, int>;
using PLL = std::pair<ll, ll>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)


int main()
{

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    int w, h;
    char a, b, c;
    cin >> w >> h >> c;
    

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

    return 0;
}