using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;
using System.Text;

public class Program
{

    public void Proc()
    {
        string inpt = Reader.ReadLine();
        int ans = 0;
        for (int i = 0; i < inpt.Length; i++) {
            ans = Math.Max(ans, GetMaxTaisyo(i, inpt));
        }
        Console.WriteLine(ans);
    }


    private int GetMaxTaisyo(int idx, String target) {
        int ans = 1;

        char[] tmp = target.ToArray();
        for (int i = 1; i < target.Length; i++) {
            int fromIdx = idx - i;
            int toIdx = idx + i;
            if (fromIdx < 0) {
                break;
            }
            if(toIdx >= target.Length) {
                break;
            }
            if(tmp[idx-i]!=tmp[idx+i]) {
                tmp[idx - i] = ' ';
                tmp[idx + i] = ' ';
            }
            ans = Math.Max(ans, tmp.Skip(fromIdx).Take(i * 2 + 1).Count(a => a != ' '));
        }

        tmp = target.ToArray();
        for (int i = 1; i < target.Length; i++) {
            int fromidx = idx - i + 1;
            int toIdx = idx + i;
            if (fromidx < 0)
            {
                break;
            }
            if (toIdx >= target.Length)
            {
                break;
            }
            if(tmp[fromidx] != tmp[toIdx]) {
                tmp[fromidx] = ' ';
                tmp[toIdx] = ' ';
            }
            ans = Math.Max(ans, tmp.Skip(fromidx).Take(i * 2).Count(a => a != ' '));
        }
        return ans;
    }


    public class Reader
    {
        private static StringReader sr;
        public static bool IsDebug = false;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (sr == null)
                {
                    sr = new StringReader(InputText.Trim());
                }
                return sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        private static string InputText = @"


1145141919810


";
    }

    public static void Main(string[] args)
    {
#if DEBUG
        Reader.IsDebug = true;
#endif
        Program prg = new Program();
        prg.Proc();
    }
}