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 os
import sys
import math
from atexit import register
from io import BytesIO

sys.stdin = BytesIO(os.read(0, os.fstat(0).st_size))
sys.stdout = BytesIO()
register(lambda: os.write(1, sys.stdout.getvalue()))

input = lambda: sys.stdin.readline().rstrip('\r\n')

# ref. https://codeforces.com/blog/entry/71884
# 1) inp(), For taking integer inputs.
# 2) inlt(), For taking List inputs.
# 3) insr(), For taking string inputs. 
#           Actually it returns a List of Characters, 
#           instead of a string, which is easier to use in Python, 
#           because in Python, Strings are Immutable.
# 4) invr(), For taking space seperated integer variable inputs.

def inp():
    return(int(input()))
def inlt():
    return(list(map(int,input().split())))
def insr():
    s = input()
    return(list(s[:len(s)]))
def invr():
    return(map(int,input().split()))

def isPrime(num):

    # if 2...num has divisor of num
    # only need to check up to sqrt(num)

    n = int(math.sqrt(num))

    for i in range(2, n + 1):
        if num % i == 0:
            # divsor found
            return False

    return True

n, m = inlt()

if isPrime(m) == False:
    sys.stdout.write('NO\n')
else:
    ans = 'YES'

    for i in range(n + 1, m):
        if isPrime(i) == True:
            ans = 'NO'
            break

    sys.stdout.write(ans + '\n')