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
# A. Panoramix's Prediction
# time limit per test: 2 seconds
# memory limit per test: 256 megabytes
# input: standard input
# output: standard output
# 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.


# 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.

def checkPrime(n):
    prime = True
    if n > 1:
        for i in range(2,n):
            if n % i == 0:
                 prime = False
        return prime

def nextPrime(n):
    # 1. Check n is prime
    # 2. keep incrementing n until m is a prime number
    prime = checkPrime(n)
    m = n
    if prime == False:
        return False
    else:
        for _ in range(n, 51):
            m = m + 1
            prime = checkPrime(m)
            if prime == True:
                return m

def checkNextPrime(n, m):
    if n >= 2 and n < m and m <= 50:
        temp = nextPrime(n)
        if temp == m:
            print("YES")
        else:
            print("NO")
    else:
        print("NO")

n,m = map(int,input().split())
checkNextPrime(n,m)