using System;

namespace Palindrome01
{
	class MainClass
	{
		static void Main(string[] args)
		{
			string sentence;
			int maxLength = 0;

			sentence = Console.ReadLine();

			for (int i = 0; i < sentence.Length - 1; i++)
			{
				for (int j = i; j < sentence.Length; j++)
				{
					string temp = sentence.Substring(i, sentence.Length - j);
					int num = SearchPalidrome(temp, 0);
					if (num == sentence.Length)
						num -= 2;
					if (num > maxLength)
						maxLength = num;
				}
			}
			Console.WriteLine(maxLength);
		}

		static int SearchPalidrome(string sentence, int layer)
		{
			if (sentence.Length == 1)
				return ++layer;
			if (sentence.Length == 0)
				return layer;

			if (sentence[0] == sentence[sentence.Length - 1])
			{
				string temp = sentence.Substring(1, sentence.Length - 2);
				return SearchPalidrome(temp, layer+=2);
			}

			return 0;
		}
	}
}