let is_prime n =
  if n < 2 then false
  else if n = 2 then true
  else if ((n mod 2) = 0) then false
  else
    let sqrt_n = (int_of_float (sqrt (float_of_int n)) + 1) in
    let rec rec_is_prime p =
      let p2_1 = (p * 2) + 1 in
      if (p2_1 > sqrt_n) then true
      else if ((n mod p2_1) = 0) then false
      else rec_is_prime (p + 1) in
    rec_is_prime 1;;

let () =
  read_int () |> (fun x -> if (is_prime x) then "NO" else "YES") |> print_string;print_newline ();;