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

"""
Created on Mon Jul  6 21:28:12 2020

@author: rishi
"""
import math

def sumofno(n):
    summ=0
    while(n>0):
        summ+=n%10
        n//=10
    return summ

def get_key(val,lis): 
    for key, value in lis.items(): 
         if value == val : 
             return key 

def isprime(val):
    c=0
    for j in range(2,val):
        if(val%j)==0:
            return False
    return True
            
#print(isprime(15))
try:
    #t=int(input())
    ans=[]
    
    for i in range(1):
        n,m=input().split()
        n=int(n)
        m=int(m)
        if((m<=n) or (m%2==0)):
            ans.append("NO")
        else:
            for i in range(n+1,m+1):
                if(isprime(i)):
                    if(m==i):
                        ans.append("YES")
                        break
                    else:
                        ans.append("NO")
                        break
                if(i==m):
                    ans.append("NO")
                    
                
                    
                
                
                
                
        
    #print (ans)
    for an in ans:
        #print("hi")
        print(an)

except:
    pass
            