A.py

import numpy as np

def seachPrimeNum(N):
    max = int(np.sqrt(N))
    seachList = [i for i in range(2,N+1)]
    primeNum = []
    while seachList[0] <= max:
        primeNum.append(seachList[0])
        tmp = seachList[0]
        seachList = [i for i in seachList if i % tmp != 0]
    primeNum.extend(seachList)
    return primeNum

n = int(input())
primes = seachPrimeNum(1000000)
if n in primes:
    print('YES')
else:
    print('NO')