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
n = input()

n = [int(x) for x in n.split()]

if n[1]%2 == 0 :
    print ("NO")
else:
    temp = n[0]+1
    while True:
        flag = 0
        for s in range(2,temp):
            if temp%s == 0 :
                flag = 1
                break
        if flag == 1 :
            temp +=1
            continue
        else:
            break


    if temp == n[1]:
        print ("YES")
    else:
        print ("NO")
        



        
        
        
           
        
        
    
    




    
            
        





            
        
            

        
            



        
        
    
        



            


    
    







    



        
        
        
        


            



        
            

    


    

    



        


        



    
        
        

    







    
    
 

    

        
    
            
    




    


        



    





        
            
        
    
