import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


def sieve_of_eratosthenes(n):  # n以下の素数の全列挙
    prime_list = []
    A = [1]*(n+1)  # A[i] = iが素数なら1,その他は0
    A[0] = A[1] = 0
    for i in range(2,int(n**.5)+1):
        if A[i]:
            prime_list.append(i)
            for j in range(i**2,n+1,i):
                A[j] = 0
    for i in range(int(n**.5)+1,n+1):
        if A[i] == 1:
            prime_list.append(i)
    return prime_list


K,N = I(),I()
primes = sieve_of_eratosthenes(N)
prime_list = [p for p in primes if p >= K]


def f(n):
    if n <= 9:
        return n
    X = str(n)
    return f(sum(int(X[i]) for i in range(len(X))))


A = [(p,f(p)) for p in prime_list]
l = len(A)
for i in range(9,0,-1):
    for j in range(l-i,-1,-1):
        if len(set([A[j+k][1] for k in range(i)])) == i:
            print(A[j][0])
            exit()