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

namespace Yuki
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            string a;
            int max = s.Length == 2 && s[0].Equals(s[1]) ? 1 : 0;

            for (int i = 0; i < s.Length; i++)
            {
                a = s[i].ToString();
                for (int j = i + 1; j < s.Length; j++)
                {
                    a += s[j];
                    if (a.Length == s.Length) break;
                    char[] b = a.ToCharArray();
                    Array.Reverse(b);
                    if (a.Equals(new string(b)) && a.Length > max) max = a.Length;
                }
            }
            Console.WriteLine(max);
        }
    }
}