#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <deque>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>

#define p(s) cout<<(s)<<endl
#define REP(i,n,N) for(int i=n;i<N;i++)
#define RREP(i,n,N) for(int i=N-1;i>=n;i--)
#define CK(n,a,b) ((a)<=(n)&&(n)<(b))
#define F first
#define S second
typedef long long int ll;
using namespace std;
const int inf=1e9+7;

int H,W;
char C;
string s[2];
int main(){
    cin>>W>>H>>C;
    char odd='B', even='W';
    if(C=='B'){
        swap(odd, even);
    }
    REP(j,0,W){
        if(j%2){
            s[0]+=odd;
        }else{
            s[0]+=even;
        }
    }
    swap(odd, even);
    REP(j,0,W){
        if(j%2){
            s[1]+=odd;
        }else{
            s[1]+=even;
        }
    }
    REP(i,0,H){
        cout<<s[i%2]<<endl;
    }
    return 0;
}