human
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
 ... Can you provide a Python code to determine whether the Gauls should wait for the black day after today's victory of Asterix and Obelix?
assistant
#Here is Python code to determine whether the Gauls should wait for the black day after today's victory of Asterix and Obelix.

"""
Author : Aman Thakur
mantra: chor kya hi kar sakte hai!!
"""
import math

class Solution:
    def __init__(self):
        self.arr = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47]

    def solution(self):
        n, m = map(int, input().strip().split())
        if m in self.arr and n in self.arr and m > n and self.arr.index(m) - self.arr.index(n) == 1:
            print('YES')
        else:
            print('NO')

if __name__ == '__main__':
    ob = Solution()
    ob.solution()