#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <cmath>

using namespace std;

const int H_MAX_RT = 1e5;

vector<long long> primes;

void make_primes() {
	vector<bool> is_prime(H_MAX_RT + 100, true);
	is_prime[0] = is_prime[1] = false;

	int n = is_prime.size();
	for (int i = 2; i < n; i++) {
		if (is_prime[i]) {
			for (int j = i * 2; j < n; j += i) {
				is_prime[j] = false;
			}
		}
	}

	for (int i = 0; i < n; i++) {
		if (is_prime[i]) {
			primes.emplace_back(i);
		}
	}
}

int main() {
	make_primes();

	long long l, h;
	cin >> l >>  h;
	long long diff = h - l + 1;

	auto it = upper_bound(primes.begin(), primes.end(), sqrt(h));
	int idx = it - primes.begin();
	do {
		idx--;
	} while (primes[idx] * primes[idx] > h);


	do {
		long long prime2 = primes[idx] * primes[idx];
		for (long long i = h; i >= l && i >= prime2; i--) {
			if (i % primes[idx] == 0) {
				long long tmp = i / primes[idx];
				if (tmp == 1) {
					continue;
				}
				bool is_ok = true;

				for (int i = 0; i < idx; i++) {
					if (tmp % primes[i] == 0) {
						is_ok = false;
					}
				}
				if (is_ok) {
					cout << i << endl;
					return 0;
				}
			}
		}

		idx--;
	} while (idx >= 0);

	return 0;
}