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

namespace No273
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			var s = Console.ReadLine ();
			var r = new string(s.Reverse ().ToArray());

			int maxMatch = 0;
			for (int i = 1; i < s.Length; i++) {
				int a = 0;
				for (int k = 0; k + i< s.Length; k++) {
					if (s [i + k] == r [k]) {
						a++;
						maxMatch = Math.Max (maxMatch, a);
					} else {
						a = 0;
					}
				}
			}
			for (int i = 0; i < s.Length-1; i++) {
				int a = 0;
				for (int k = 1; k + i< s.Length; k++) {
					if (s [i + k] == r [k]) {
						a++;
						maxMatch = Math.Max (maxMatch, a);
					} else {
						a = 0;
					}
				}
			}
			Console.WriteLine (maxMatch.ToString ());
		}
	}
}