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 python
# -*- coding: UTF-8 -*-
import time
import sys, io
import re, math
#start = time.clock()
n,m=map(int, raw_input().split())
#l=[int(x) for x in raw_input().split()]

def prime(m):
    l=[True for _ in range(m+1)]
    i=2
    while i**2<=m:
        if l[i]:
            j=i+i
            while j<=m:
                l[j]=False
                j+=i
        i+=1
    lis=[i for i in range(m+1) if l[i] and i>=2]
    if m in lis and n in lis:
        if lis.index(m)-lis.index(n)==1:
            print 'YES'
        else:
            print 'NO'
    else:
        print 'NO'
#    return lis

if __name__=='__main__':
    prime(m)