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 re
import sys
from bisect import bisect, bisect_left, insort, insort_left
from collections import Counter, defaultdict, deque
from copy import deepcopy
from decimal import Decimal
from itertools import (
    accumulate, combinations, combinations_with_replacement, groupby,
    permutations, product)
from math import (acos, asin, atan, ceil, cos, degrees, factorial, gcd, hypot,
                  log2, pi, radians, sin, sqrt, tan)
from operator import itemgetter, mul
from string import ascii_lowercase, ascii_uppercase, digits


def inp():
    return(int(input()))


def inlist():
    return(list(map(int, input().split())))


def instr():
    s = input()
    return(list(s[:len(s)]))


def invr():
    return(map(int, input().split()))


def is_isprime(n):
    if n == 0 or n == 1:
        return False
    if n == 2:
        return True
    limit = int(sqrt(n)+1)
    for i in range(2, limit+1):
        if n % i == 0:
            return False
    return True


a, b = invr()
nxt_p = -1
for i in range(a+1, b+1):
    if is_isprime(i):
        nxt_p = i
        break
if nxt_p == b:
    print("YES")
else:
    print("NO")
