use std::io::*;
use std::str::FromStr;

#[allow(dead_code)]
fn get_line() -> String {
    let stdin = stdin();
    let mut line = String::new();
    stdin.lock().read_line(&mut line).expect("io error.");
    line.trim().to_string()
}

#[allow(dead_code)]
fn get_word<T: FromStr>() -> T {
    (&get_line()).parse().ok().expect("parse error.")
}

#[allow(dead_code)]
fn get_vec<T: FromStr>() -> Vec<T> {
    (&get_line()).split(' ').map(|x| x.parse().ok().expect("parse error.")).collect()
}

fn main() {
    let color: Vec<char> = "BW".chars().collect();

    let v = get_vec::<String>();
    let w: u64 = (&v[0]).parse().ok().unwrap();
    let h: u64 = (&v[1]).parse().ok().unwrap();
    let c: u64 = if v[2].chars().next().unwrap() == 'B' {0} else {1};

    for i in 0..h {
        for j in 0..w {
            print!("{}", color[((i + j + c) % 2) as usize]);
        }
        println!("");
    }
}