#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(),x.end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<class T> inline bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T&a,T b){if(a>b){a=b;return 1;}return 0;}
using ll = long long;

int w,h;
char c,d;

int main () {
    ios::sync_with_stdio(false); 
    cin.tie(0);

    cin >> w >> h >> c;
    c=='B' ? d='W' : d='B';
    rep(i,h){
        rep(j,w) cout << ((i+j)%2 ? d : c);
        cout << endl;
    }
}