#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<string>
#include<vector>
#include<map>
#include<list>
#include<stack>
#include<queue>
#include<climits> //INT_MIN/MAX


using namespace std;


#define llong long long
#define int long long

bool prime[100001];

llong least_prime(llong x) {
    for (int i = 2; i * i <= x; i++) if (x % i == 0)
        return i;
    return x;
}

signed main() 
{
    for (int i = 2; i <= 100000; i++)
        prime[i] = true;
    for (int i = 2; i * i <= 100000; i++) if (prime[i]) {
        for (int j = i*2; j <= 100000; j+=i)
            prime[j] = false;
    }//素数がダメっぽかった？


    llong l, h;
    cin >> l >> h;
    for (int x = sqrt(h); ; x--) {
        if (prime[x]) for (llong y = h / x; y * x >= l; y--) {
            if (least_prime(y) >= x) {
                cout << y * x << endl;
                return 0;
            }
        }
    }
    return 0;
}