#!/usr/bin/python3
def sieve(n):
    is_prime = [0, 0] + [1] * (n-1)
    sq = int(n ** .5)
    for i in range(2, sq+1):
        if is_prime[i]:
            for j in range(i*i, n+1, i):
                is_prime[j] = 0
    return [i for i, p in enumerate(is_prime) if p]

from collections import defaultdict

def factorize(n):
    res = defaultdict(int)
    d = 2
    while d * d <= n:
        while n % d == 0:
            res[d] += 1
            n //= d
        d += 1
    if n > 1:
        res[n] += 1
    return res

L, H = map(int, input().split())
primes = sieve(10**5 + 100)
for p in primes[::-1]:
    l = (L+p-1) // p
    h = H // p
    for d in reversed(range(max(p, l), h+1)):
        fac = factorize(d)
        if min(list(fac.keys()) + [p]) == p:
            res = p * d
            print(res)
            exit(0)