#include <bits/stdc++.h>
using namespace std;

int main() {
    int h, w;
    char c;
    cin >> w >> h >> c;
    char d = (c == 'W' ? 'B' : 'W');
    
    vector<vector<char>> ans(h, vector<char>(w));
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            if ((i + j) & 1) ans[i][j] = d;
            else ans[i][j] = c;
        }
    }
    
    for (const auto &v : ans) {
        for (const auto &e : v) cout << e;
        cout << '\n';
    }
    
    return 0;
}