use std::io::Read;

fn main() {
    let mut buf = String::new();
    std::io::stdin().read_to_string(&mut buf).unwrap();
    let mut iter = buf.split_whitespace();

    let l: i32 = iter.next().unwrap().parse().unwrap();
    let r: i32 = iter.next().unwrap().parse().unwrap();
    let m: i32 = iter.next().unwrap().parse().unwrap();
    let k: i32 = iter.next().unwrap().parse().unwrap();

    if (l * k + m - 1) / m != (r * k + m) / m {
        println!("Yes");
    } else {
        println!("No");
    }
}