use std::io::{Read, stdin};

fn main() {
    let mut buf = String::new();
    stdin().read_to_string(&mut buf).unwrap();
    let mut tok = buf.split_whitespace();
    let mut get = || tok.next().unwrap();
    macro_rules! get {
        ($t:ty) => (get().parse::<$t>().unwrap());
        () => (get!(i64));
    }
    
    let n = get!();
    let _m = get!();
    let mut ok = false;
    for _ in 0..n {
        let s = get!(String);
        ok |= s.contains("LOVE");
    }
    if ok {
        println!("YES");
    } else {
        println!("NO");
    }
}