using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static string InputPattern = "Input4";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("ABACDDCEFGFE");
            //5
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("ZZ");
            //1
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("AABAAABBABBABBBAAABAA");
            //8
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        string S = InputList[0];

        //回文判定
        Predicate<string> IsKaibun = (pStr) =>
            pStr.SequenceEqual(pStr.Reverse());

        //最長の回文以外は、1文字の回文とみなして
        //ナイーブに最長の回文を探す
        var KaibunList = new List<string>();
        for (int I = 0; I <= S.Length - 1; I++) {
            for (int J = S.Length - 1; I <= J; J--) {
                string wkStr = S.Substring(I, J - I + 1);
                if (IsKaibun(wkStr) == false) continue;
                KaibunList.Add(wkStr);
                break;
            }
        }

        //分解してない回文をRemove
        KaibunList.RemoveAll(X => X == S);

        Console.WriteLine(KaibunList.Max(X => X.Length));
    }
}