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 sys

def readints() :
    l = sys.stdin.readline()
    return map(int, l.split(' '))

def readstring() :
    l = sys.stdin.readline()[:-1]
    return l

def readint() :
    l = sys.stdin.readline()
    return int(l)

def clearchars(s, chars) :
    for c in chars :
        s = s.replace(c, '')
    return s

def gcd(a, b) :
    if (a < b ) :
        a, b = b, a
    if b == 0 :
        return a
    return gcd(b, a % b)

def hist(a) :
    h = {}
    for x in a :
        try : 
            h[x] += 1
        except KeyError :
            h[x] = 1
    return h

def lucky(n) :
    s = set(str(n))
    return all(map(lambda x: x in '47', s))    

def yslice(a, j) :
    return map(lambda x: x[j], a)

def dist2(a, b) :
    return ((a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2) ** 0.5

def chain_len(a) :
    l = .0
    for d, e in zip(a, a[1:]) :
        l += dist2(d, e)
    return l

def is_prime(x) :
    sq = int(x ** 0.5) 
    for i in range(2, sq + 1) :
        if x % i == 0 :
            return False
    return True

def noe() :
    print "NO"
    exit(0)

def yese() :
    print "YES"
    exit(0)

n, m = readints()

if not is_prime(m) :
    noe()

for i in range(n + 1, m) :
    if is_prime(i) :
        noe()

yese()
