#include <iostream>
using namespace std;

int main(){
    int W, H;
    char C;
    
    cin >> W >> H >> C;
    
    string color;
    if(C == 'W'){
        color = "WB";
    } else {
        color = "BW";
    }
    
    for(int y=0;y<H;y++){
        for(int x=0;x<W;x++){
            cout << color[(y+x)%2];
        }
        cout << endl;
    }
    
    return 0;
}