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
#!/usr/bin/env python2
# -*- coding: utf-8 -*-
import sys
input = sys.stdin
output = sys.stdout

from math import sqrt
from itertools import repeat

def primes_eratosthene_leq_simple(N):
    primes = [True]*(N+1)
    primes[0] = False
    primes[1] = False
    SQRT_N = int(sqrt(N))
    for i in range(2,SQRT_N+1):
        if primes[i]:
            primes[i*i:N+1:i] = repeat(False, len(primes[i*i:N+1:i]))
    P = []
    for p,prime in enumerate(primes):
        if prime:
            P.append(p)
    return P

def solve(n,m):
    P = primes_eratosthene_leq_simple(100)
    i = P.index(n)
    if P[i+1] == m:
        return 'YES'
    return 'NO'

S  = input.readline().strip().split(' ')
n = int(S[0])
m = int(S[1])
assert 2<=n and n<m and m<=50

a = solve(n,m)
output.write('%s\n' % a)
