fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().split_whitespace()
      .map(|e| e.parse().ok().unwrap()).collect()
}
fn main(){
   let mut v :Vec<usize> = read_vec(); 
   v.sort();
   if v[0] + 1 == v[1] && v[0] + 2 == v[2] && v[0] + 3 == v[3] {
        println!("Yes");
   }else{
        println!("No");
   }
}