#[macro_export]
macro_rules! setup {
    { mut $input:ident: SplitWhitespace $(,)? } => {
        use std::io::Read;
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).ok();
        let mut $input = buf.split_whitespace();
    };
}

#[macro_export]
macro_rules! parse_next {
    ($str_iter:expr) => {
        $str_iter.next().unwrap().parse().ok().unwrap()
    };
}

fn main() {
    setup! { mut input: SplitWhitespace };

    let w: usize = parse_next!(input);
    let h: usize = parse_next!(input);
    let c: char = parse_next!(input);

    let ans = (|| {
        let mut pattern = String::from("");
        for i in 1..=h {
            for j in 1..=w {
                match (i % 2, j % 2) {
                    (1, 1) | (0, 0) => {
                        pattern.push(match c {
                            'B' => 'B',
                            'W' => 'W',
                            _ => unreachable!(),
                        });
                    }
                    (1, 0) | (0, 1) => {
                        pattern.push(match c {
                            'B' => 'W',
                            'W' => 'B',
                            _ => unreachable!(),
                        });
                    }
                    _ => unreachable!(),
                }
            }
            if i != h {
                pattern.push('\n');
            }
        }
        pattern
    })();

    println!("{}", ans);
}