K = int(raw_input())
N = int(raw_input())


def foldnum(n):
    if n == 0:
        return 0
    if n % 9 == 0:
        return 9
    return n % 9


def eratos(n):
    list = xrange(2, n + 1)
    ans = []
    while len(list):
        ans.append(list[0])
        list = filter(lambda x: x % list[0] > 0, list)
    return ans


def eratos2(n):
    table = [True] * (n + 1)
    table[0] = table[1] = False
    a = 2
    while a * a <= n:
        if table[a]:
            k = 2
            while a * k <= n:
                table[a * k] = False
                k += 1
        a += 1
    ans = []
    for i, v in enumerate(table):
        if v:
            ans.append(i)
    return ans


prime_map = filter(lambda x: x >= K, eratos2(N))
L = len(prime_map)
a = 0
b = 0
mx = 0
total = 0
check = [False] * 10
maxIndex = 0
while a < L:
    while b < L:
        v = foldnum(prime_map[b])
        if check[v]:
            break
        b += 1
        check[v] = True
    if mx <= b - a - 1:
        mx = b - a - 1
        maxIndex = a
    v = foldnum(prime_map[a])
    check[v] = False
    a += 1
print prime_map[maxIndex]