#include "bits/stdc++.h"
using namespace std;

#define REP(i, n) for(int i=0; i<(n); i++)

int W,H;
char C;
signed main()
{
    cin>>W>>H>>C;
    char b[2] = {'W','B'};
    if (C == 'B') swap(b[0],b[1]);
    REP(y,H) {
        REP(x,W) {
            cout << b[(x+y)%2];
        }
        cout << endl;
    }
    return 0;
}