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
import sys
import math
import bisect
import itertools
import random

def pow_mod(a, n, m):
    if n == 0:
        return 1
    if n == 1:
        return a % m
    ans = pow_mod(a, n // 2, m)
    ans = ans * ans % m
    if n % 2 == 1:
        ans = ans * a % m
    return ans

def MillerRabin_PrimalityTesting(n):
    if n == 2 or n == 3:
        return True
    if n % 2 == 0:
        return False
    if n % 3 == 0:
        return False
    R = 0
    D = n - 1
    while D % 2 == 0:
        R += 1
        D //= 2
    #print([n, R, D])
    for _ in range(random.randint(10, 15)):
        A = random.randint(2, n - 1)
        X = pow_mod(A, D, n)
        #X = A ** D % n
        if X == 1 or X == n - 1:
            continue
        flag = 0
        for i in range(1, R):
            X = pow_mod(X, 2, n)
            #X = X ** 2 % n
            if X == 1:
                return False
            if X == n - 1:
                flag = 1
                break
        if flag == 1:
            continue
        return False
    return True

def main():
    n, m = map(int, input().split())
    s = None
    for i in range(n + 1, 10 ** 9):
        if MillerRabin_PrimalityTesting(i):
            s = i
            break
    if s == m:
        print('YES')
    else:
        print('NO')

if __name__ == "__main__":
    main()
