#include <bits/stdc++.h>
using namespace std;

long long factor(long long n) {
	for (long long i = 2; i * i <= n; i++) {
		if (n % i == 0) return i;
	}
	return n;
}

int main() {
	long long L, H;
	cin >> L >> H;

	const int N = 1e5 + 100;
	vector<long long> primes;
	vector<bool> is_prime(N, true);

	for (long long i = 2; i < N; i++) {
		if (is_prime[i]) {
			primes.push_back(i);
			for (long long j = i * 2; j < N; j += i) {
				is_prime[j] = false;
			}
		}
	}

	reverse(primes.begin(), primes.end());

	for (long long p : primes) {
		if (p * p > H) continue;
		for (long long q = H / p; p * q >= L; q--) {
			if (factor(q) >= p) {
				cout << p * q << endl;
				return 0;
			}
		}
	}
}