using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        var s = Console.ReadLine().Trim();
        getAns(s);

    }
    static int check2(string s, int p)
    {
        var sL = s.Length;
        var d = 0;
        var count = 0;
        while (true)
        {
            if (p + d + 1 == sL | p - d < 0) break;
            if (s[p - d] == s[p + d + 1])
            {
                count += 2;
                if (count == sL) { count -= 2; break; }
            }
            else break;
            d++;
        }
        return count;
    }
    static int check1(string s, int p)
    {
        var sL = s.Length;
        var d = 1;
        var count = 1;
        while (true)
        {
            if (p + d == sL | p - d < 0) break;
            if (s[p + d] == s[p - d])
            {
                count += 2;
                if (count == sL) { count -= 2; break; }
            }
            else break;
            d++;
        }
        return count;
    }
    static void getAns(string s)
    {
        var sL = s.Length;
        var ans = 1;
        for (int i = 0; i < sL; i++)
        {
            var t0 = check1(s, i);
            var t1 = check2(s, i);
            ans = Max(ans, t0);
            ans = Max(ans, t1);
        }
        Console.WriteLine(ans);
    }
}