A prime number is a number which has exactly two distinct divisors: one and itself. For example, numbers 2, 7, 3 are prime, and 1, 6, 4 are not.

The next prime number after x is the smallest prime number greater than x. For example, the next prime number after 2 is 3, and the next prime number after 3 is 5. Note that there is exactly one next prime number after each number. So 5 is not the next prime number for 2.

One cold April morning Panoramix predicted that soon Kakofonix will break free from his straitjacket, and this will be a black day for the residents of the Gallic countryside.

Panoramix's prophecy tells that if some day Asterix and Obelix beat exactly x Roman soldiers, where x is a prime number, and next day they beat exactly y Roman soldiers, where y is the next prime number after x, then it's time to wait for Armageddon, for nothing can shut Kakofonix up while he sings his infernal song.

Yesterday the Gauls beat n Roman soldiers and it turned out that the number n was prime! Today their victims were a troop of m Romans (m > n). Determine whether the Gauls should wait for the black day after today's victory of Asterix and Obelix?

Input

The first and only input line contains two positive integers — n and m (2 ≤ n < m ≤ 50). It is guaranteed that n is prime.

Pretests contain all the cases with restrictions 2 ≤ n < m ≤ 4.

Output

Print YES, if m is the next prime number after n, or NO otherwise.

Examples

Input

3 5


Output

YES

Input

7 11


Output

YES

Input

7 9


Output

NO
__author__ = 'Devesh Bajpai'

'''
https://codeforces.com/problemset/problem/80/A

Solution: The idea is to check numbers in the range [n+1, m) if anyone of them is prime or not. If so, then surely m
is not the next prime number. If that range doesn't find a prime number, we need to check if m itself is prime or not.
Accordingly, we return the result.  

Improvement: We can surely use Sieve of Eratosthenes for a better way to figure out if a number is prime or not.
'''

import math


def is_prime(x):

    for i in xrange(2, int(math.sqrt(x))+1):

        if x % i == 0:
            return False

    return True


def solve(n, m):

    for i in xrange(n+1, m):

        if is_prime(i):
            return "NO"

    return "YES" if is_prime(m) else "NO"


if __name__ == "__main__":

    n,m = map(int, raw_input().split(" "))
    print solve(n, m)