fn main() { let mut hwnk = String::new(); std::io::stdin().read_line(&mut hwnk).ok(); let hwnk: Vec = hwnk.trim().split_whitespace().map(|s| s.parse().unwrap()).collect(); let h = hwnk[0]; let w = hwnk[1]; let n = hwnk[2]; let k = hwnk[3]; if (h * w - 1) % n + 1 == k { println!("YES"); } else { println!("NO"); } }