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

class Solution
{
    static void Main()
    {
        var s = Console.ReadLine();
        var bestLen = 0;

        for (int i = 0; i < s.Length; i++)
        {
            int len = 1;
            int left = i - 1;
            int right = i + 1;
            while (left >= 0 && right < s.Length)
            {
                if (s[left] == s[right])
                {
                    len += 2;
                }
                left--;
                right++;
            }

            bestLen = Math.Max(len, bestLen);
        }
        Console.WriteLine(bestLen);
    }
}