using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Text;
using static System.Console;
using static System.Convert;
using static System.Math;
using static Extentions;

class IO
{
    int idx;
    string[] input = In.ReadToEnd().Split(new[] { " ", "\n", "\r" },
        StringSplitOptions.RemoveEmptyEntries);

    T Get<T>(Func<string, T> parser) => parser(input[idx++]);

    public string S => Get(s => s);
    public char C => Get(char.Parse);
    public int I => Get(int.Parse);
    public long L => Get(long.Parse);
    public double F => Get(double.Parse);
    public decimal D => Get(decimal.Parse);
    public BigInteger B => Get(BigInteger.Parse);

    T[] Gets<T>(int n, Func<string, T> parser)
        => input.Skip((idx += n) - n).Take(n).Select(parser).ToArray();

    public string[] Ss(int n) => Gets(n, s => s);
    public char[] Cs(int n) => Gets(n, char.Parse);
    public int[] Is(int n) => Gets(n, int.Parse);
    public long[] Ls(int n) => Gets(n, long.Parse);
    public double[] Fs(int n) => Gets(n, double.Parse);
    public decimal[] Ds(int n) => Gets(n, decimal.Parse);
    public BigInteger[] Bs(int n) => Gets(n, BigInteger.Parse);

    public void Write<T>(params T[] xs) => WriteLine(string.Join(" ", xs));
    public void Write(params object[] xs) => WriteLine(string.Join(" ", xs));
}

#region Library

struct ComparablePair<T1, T2> : IComparable<ComparablePair<T1, T2>>
    where T1 : IComparable<T1>
    where T2 : IComparable<T2>
{
    public T1 First;
    public T2 Second;

    public ComparablePair(T1 first, T2 second)
    {
        First = first;
        Second = second;
    }

    public int CompareTo(ComparablePair<T1, T2> other)
    {
        var t = other.First.CompareTo(First);
        if (t == 0) t = other.Second.CompareTo(Second);
        return t;
    }

    public override string ToString() => $"({First}, {Second})";
}

static class ComparablePair
{
    public static ComparablePair<T1, T2> Create<T1, T2>(T1 first, T2 second)
        where T1 : IComparable<T1>
        where T2 : IComparable<T2>
        => new ComparablePair<T1, T2>(first, second);
}

static partial class Extentions
{
    // O(N log log N)
    public static int[] Primes(int n)
    {
        if (n < 2) return Array.Empty<int>();

        var flgs = new bool[n + 1];
        for (var i = 3; i * i < n; i += 2)
            if (!flgs[i]) for (var j = i * i; j <= n; j += i) flgs[j] = true;

        var list = new List<int>() { 2 };
        for (var i = 3; i <= n; i += 2) if (!flgs[i]) list.Add(i);
        return list.ToArray();
    }
}

#endregion

static class Program
{
    public static void Main()
    {
        var sw = new StreamWriter(OpenStandardOutput()) { NewLine = "\n" };
#if DEBUG
        sw.AutoFlush = true;
#else
        sw.AutoFlush = false;
#endif
        SetOut(sw);
        Solve(new IO());
        Out.Flush();
    }

    static int Hash(int n) => n % 9;

    static void Solve(IO io)
    {
        var k = io.I;
        var n = io.I;

        var pk = Primes(k);
        var pn = Primes(n);
        var ps = pn.Where(x => !pk.Contains(x)).ToArray();
        var hs = ps.Select(Hash).ToArray();

        var set = new HashSet<int>();
        var rec = new SortedSet<ComparablePair<int, int>>();
        var headi = 0;

        for (var i = 0; i < hs.Length; i++)
        {
            if (!set.Add(hs[i]))
            {
                rec.Add(ComparablePair.Create(i - headi, ps[headi]));
                while (!set.Add(hs[i])) set.Remove(hs[headi++]);
            }
        }

        rec.Add(ComparablePair.Create(hs.Length - headi, ps[headi]));
        io.Write(rec.First().Second);
    }
}