#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int w, h;
    char c;
    vector<string> v;
    
    cin >> w >> std::ws >> h >> std::ws >> c;
    
    char stt_color = c;
    for (int i = 0; i < h; i++) {
        string line;
        char curr_color = stt_color;
        for (int j = 0; j < w; j++) {
            line += curr_color;
            if (curr_color == 'W') {
                curr_color = 'B';
            } else {
                curr_color = 'W';
            }
        }
        
        v.push_back(line);
        
        if (stt_color == 'W') {
            stt_color = 'B';
        } else {
            stt_color = 'W';
        }
    }
    
    for (int k = 0; k < v.size(); k++) {
        cout << v.at(k) << endl;
    }
    
    return 0;
}