#!/usr/bin/ python3.8
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

U = 10 ** 5 + 10
is_prime = np.zeros(U, np.bool)
is_prime[2] = 1
is_prime[3::2] = 1

for p in range(3, U, 2):
    if p * p > U:
        break
    if is_prime[p]:
        is_prime[p * p:: p + p] = 0
primes = np.where(is_prime)[0]


def find_smallest_prime(N):
    div = primes[N % primes == 0]
    if len(div) == 0:
        return 0  # 素数はこうしておく
    elif div[0] == N:
        return 0
    else:
        return div[0]


def solve(L, H):
    p = primes[primes ** 2 <= H][-1]
    if p * p >= L:
        L = p * p
    best_p = 0
    best_n = 0
    for n in range(H, L - 1, -1):
        p = find_smallest_prime(n)
        if p > best_p:
            best_p = p
            best_n = n
    return best_n


L, H = map(int, read().split())
print(solve(L, H))