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
from itertools import product
from math import ceil

def binary_table(string_with_all_characters, length_to_make):
    return [''.join(x) for x in product(string_with_all_characters, repeat=length_to_make)]


def all_possible_substrings(string):
    return [string[i: j] for i in range(len(string)) for j in range(i + 1, len(string) + 1)]


def number_of_substrings(length):
    return int(length * (length + 1) / 2)


def is_prime(num):
    for i in range(2, num):
        if num / i == int(num / i) and num != i:
            return False

    return True



#for enumeration in range(int(input())):
x, d = map(int, input().split())
broke = False
for i in range(x + 1, 51):
    if is_prime(i):
        if i == d:
            print('YES')
            broke  = True
            break
        else:
            print('NO')
            broke  = True

            break
if not broke:
    print('NO')