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 sys import stdin,stdout
from math import gcd,sqrt,floor,ceil
import random
# Fast I/O
input = stdin.readline
#print = stdout.write

def list_inp(x):return list(map(x,input().split()))
def map_inp(x):return map(x,input().split())

def lcm(a,b): return (a*b)//gcd(a,b)

def binpowm(a,b,m):
	'''
		For calculating  (x^n % m)  Efficiently
	'''
	a %= m
	res = 1
	while(b>0):
		if(b&1):
			res = res * a % m
		a = a * a % m
		b >>= 1
	return res

def FermatLittle(n):
	k = 4
	for i in range(k):
		x = random.randint(1,n-1)
		if (binpowm(x,(n-1),n)) != 1:
			return "composite"
	return "prime"

n,m = map_inp(int)

if FermatLittle(n) == 'prime':
    d = 0
    for i in range(n+1,m+10):
        if FermatLittle(i) == 'prime':
            d = i
            break
    if d == m:
        print('YES')
    else:
        print('NO')
else:
    print('NO')
