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
def is_prime(n):
  if n == 2 or n == 3: 
      return True
  if n < 2 or n%2 == 0: 
      return False
  if n < 9: 
      return True
  if n%3 == 0: 
      return False
  r = int(n**0.5)
  f = 5
  
  while f <= r:
    if n%f == 0: 
        return False
    if n%(f+2) == 0: 
        return False
    f +=6
  
  return True 
  
next_prime = {2: 3, 3: 5, 5: 7, 7: 11, 11: 13, 13: 17, 17: 19, 19: 23, 23: 29, 29: 31, 31: 37, 37: 41, 41: 43, 43: 47, 47: 53, 53: 59}

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

print('YES' if next_prime[n] == m else 'NO')