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
# n=int(input())
# s1=0
# s2=0
# s3=0
# for _ in range(n):
#     x,y,z=(map(int,input().split()))
#     s1=s1+x
#     s2=s2+y
#     s3=s3+z
#
# if s1==0 and s2==0 and s3==0:
#     print("YES")
# else:
#     print("NO")

# l=[]
# for i in range(5):
#     arr=list(map(int,input().split()))
#     l.append(arr)
# # print(l)
# x,y=3,3
# for i in range(1,6):
#     for j in range(1,6):
#         if l[i-1][j-1]==1:
#             print(abs(x-i)+abs(y-j))


# n,t=map(int,input().split())
# s=input()
#
# for i in range(t):
#
#
#     s=s.replace("BG",'GB')
#
#
# print(s)

# s=input()
# for i in range(len(s)):
#     s = s.replace("--", '2')
#     s = s.replace("-.", "1")
#     s=s.replace(".",'0')
#
#
#
# print(s)
# n=int(input())
# n = n + 1
# res = set(map(int, str(n)))
# # print(res)
#
# while len(res)!=4:
#     n=n+1
#     res = set(map(int, str(n)))
#     if len(res)==4:
#         break
#
# print(n)
#
# s=input()
#
#
# t=s[0].upper()+s[1:]
#
# print(t)
# def lucky(s):
#     c=0
#     for i in range(len(s)-1):
#         if s[i]==s[i+1]:
#             c+=1
#     return(c)
#
#
# n=int(input())
# s = input()
#
# print(lucky(s))
def prime(n):
    for i in range(2,n):
        if n%i==0:
            return False
    return True
def ans(n,m):

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

        if (prime(i)==True) :
            if i==m:
                return("YES")
            else:
                return("NO")
    return("NO")
n,m=map(int,input().split())
print(ans(n,m))
