#include <bits/stdc++.h>

using ll = long long;
using ull = unsigned long long;
using ld = long double;
#define rep(i,a,b) for (int i = a; i < b; i++)
#define irep(i,a,b) for (int i = a; i > b; i--)
#define print(n) cout << n << endl
#define rup(a,b) (a+b-1)/b

using namespace std;

int main(){
    cout << fixed << setprecision(15);
    
    int w,h;
    cin>>w>>h;
    string s;
    cin>>s;
    if (s=="W") s = "WB";
    else s = "BW";
    int now = 1;
    rep(i,0,h){
        string ns = "";
    rep(j,0,w){
        if ((i+j)%2 == 0) ns += s[0];
        else ns += s[1];
    }
    print(ns);
    }
    
    //system("pause");
    return 0;
}