import strutils, math
let N = stdin.readLine.parseInt

proc isPrime(x: int): bool =
  if x != 2:
    if x == 1 or (x mod 2 == 0): return false

    for i in countup(3, int.high, 2):
      if i > (x + 1) div i: break
      if x mod i == 0: return false

  result = true

echo if N.isPrime or N == 1: "NO" else: "YES"