#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

long long min_prime_check(long long x) {
	if (x % 2 == 0) return 2;
	for (long long i = 3; i*i <= x; i += 2) {
		if (x % i == 0)return i;
	}
	return x;
}

int main() {
	cin.tie(0); ios::sync_with_stdio(false);
	long long L, H; cin >> L >> H;
	long long P = 2, Ans = 0;

	if (L % 2 == 0) {
		Ans = L;
	}
	else {
		Ans = L + 1;
	}
	for (long long i = L + 1 - L % 2; i <= H; i += 2) {
		long long temp = min_prime_check(i);
		if (temp != i && temp >= P) {
			P = temp;
			Ans = i;
		}
	}
	cout << Ans << endl;
}