fn main() {
    let stdin = std::io::read_to_string(std::io::stdin()).unwrap();
    let mut stdin = stdin.split_ascii_whitespace();

    let n: usize = stdin.next().unwrap().parse().unwrap();
    let _m: usize = stdin.next().unwrap().parse().unwrap();
    let s: Vec<String> = (0..n)
        .map(|_| stdin.next().unwrap().parse().unwrap())
        .collect();

    println!("{}", output(solve(s)));
}

fn solve(s: Vec<String>) -> bool {
    const TARGET: &[u8] = "LOVE".as_bytes();
    s.into_iter()
        .any(|s| s.into_bytes().windows(4).any(|s| s == TARGET))
}

fn output(ans: bool) -> &'static str {
    match ans {
        true => "YES",
        false => "NO",
    }
}