using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;


class Magatro
{
    static void Main()
    {
        long L, H;
        string[] s = Console.ReadLine().Split(' ');
        L = long.Parse(s[0]);
        H = long.Parse(s[1]);
        long rootH = (int)Math.Sqrt(H);
        long ans = 0;
        long max=0;
        for(long i = 2; i <= rootH; i++)
        {
            for(long j = i; j <= H / i; j++)
            {
                if (i * j < L)
                {
                    continue;
                }
                long mins = Math.Min(MinSoinsu(i),MinSoinsu(j));
                if (max <= mins)
                {
                    max = mins;
                    ans = i * j;
                }
            }
        }
        Console.WriteLine(ans);
    }
    static long MinSoinsu(long n)
    {
        if (n % 2 == 0)
        {
            return 2;

        }
        for(int i = 3; i <= Math.Sqrt(n); i += 2)
        {
            if (n % i == 0)
            {
                return i;
            }
        }
        return n;
    }
}