from operator import sub,add,floordiv,mul
import sys
N=int(input())
t=floordiv(N,N)
u=sub(ord("i"),ord("A"))
s=add(t,t)
if N==t:
  print("NO")
  sys.exit()
if N==s:
  print("YES")
  sys.exit()
i=s
while i*i<=N:
  if pow(N,t,i)==t:
    print("NO")
    break
  i+=t
else:
  print("YES")