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 itertools
import sys
import decimal
import collections
import math
import itertools as it

def readArray(type= int):
    line = input()
    return [type(x) for x in line.split()]

primes = None

def genPrimes():
    global  primes

    n = 100
    primes = [True] * n

    primes[0] = primes[1] = False
    lim = round(math.sqrt(n))

    for x in range(3, lim, 2):
        if not primes[x]:
            continue

        for nx in range(x*x, n, 2*x):
            primes[nx]= False

    return primes

def isPrime(n):
    global primes
    return n == 2  or primes[n] and n%2 != 0

def getNextPrime(x):
    global primes

    if x == 2:
        return 3

    for i in range(x+2, 100, 2):
        if primes[i]:
            return i

def solve():
    global primes
    primes = genPrimes()

    a, b = readArray()


    print('YES' if b == getNextPrime(a) else 'NO')

    # for p, x in enumerate(primes):
    #     if x and p % 2 != 0:
    #         print(p)

if __name__ == '__main__':
    # sys.stdin = open('input.txt')
    solve()

