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

class Program
{
    public void Proc()
    {
        Reader.IsDebug = false;
        int ans = this.GetAns(Reader.ReadLine());
        Console.WriteLine(ans);

    }
    private int GetAns(string inpt) {
        int ans  = 1;
        
        for(int i=0; i<inpt.Length; i++) {
            // i を中央と考えた場合
            int len = 1;
            for(int j=0; i  - j >= 0 && i + j < inpt.Length &&  1 + (j * 2) < inpt.Length; j++) {
                if(inpt[i-j] != inpt[i+j]) {
                    break;
                } else
                {
                    len = 1 + (j * 2);
                }
            }
            ans = Math.Max(ans, len);
            // i を偶数この文字列の左側とした場合
            len = 1;
            if(i < inpt.Length - 1 && inpt[i] == inpt[i+1]) {
                for(int j=0; i-j >= 0 && i+1+j < inpt.Length && 2 + (j * 2) < inpt.Length; j++) {
                    if(inpt[i-j] != inpt[i+1+j]) {
                        break;
                    } else
                    {
                        len = 2 + (j * 2);
                    }
                }
                ans = Math.Max(ans, len);
            }
        }
        return ans;
    }

    public class Reader
    {
        public static bool IsDebug = true;
        private static String PlainInput = @"


ZZ




 
";
        private static System.IO.StringReader Sr = null;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (Sr == null)
                {
                    Sr = new System.IO.StringReader(PlainInput.Trim());
                }
                return Sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        public static int[] GetInt(char delimiter = ' ', bool trim = false)
        {
            string inptStr = ReadLine();
            if (trim)
            {
                inptStr = inptStr.Trim();
            }
            string[] inpt = inptStr.Split(delimiter);
            int[] ret = new int[inpt.Length];
            for (int i = 0; i < inpt.Length; i++)
            {
                ret[i] = int.Parse(inpt[i]);
            }
            return ret;
        }
    }
    static void Main()
    {
        Program prg = new Program();
        prg.Proc();
    }
}