use proconio::{input, marker::Chars};

fn main(){
    input!{
        n: usize,
        s: Chars,
    }

    let mut ok = false;
    for i in 0..n-2{
        if s[i..i+3] == ['4', '0', '4']{
            ok = true;
        }
    }

    println!("{}Found", if ok{""} else{"Not"});
}