using System;
using System.Linq;

namespace No273{
    public class Program{
        public static void Main(string[] args){
            var S = Console.ReadLine();

            Func<string, bool> isPalindrome = str =>{
                var s = str.ToCharArray();
                return s.SequenceEqual(s.Reverse());
            };

            var res = 0;
            for(var i = 0; i < S.Length; i++){
                for(var j = 1; j <= S.Length - i; j++){
                    var s = S.Substring(i, j);
                    if(isPalindrome(s) && s.Length != S.Length) res = Math.Max(res, s.Length);
                }
            }
            Console.WriteLine(res);
        }
    }
}