using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        var s = Console.ReadLine().Trim();
        getAns(s);
    }
    static int check1(string s, int n, int p)
    {
        var d = 0;
        var res = 0;
        while (p + d < n && p - d - 1 >= 0)
        {
            if (s[p + d] == s[p - d - 1]) res += 2;
            d++;
        }
        return res;
    }
    static int check0(string s, int n, int p)
    {
        var d = 1;
        var res = 1;
        while (p + d < n && p - d >= 0)
        {
            if (s[p + d] == s[p - d]) res += 2;
            d++;
        }
        return res;
    }
    static void getAns(string s)
    {
        var ans = 0;
        var n = s.Length;
        for (int i = 0; i < n; i++)
        {
            ans = Max(ans, check0(s, n, i));
            ans = Max(ans, check1(s, n, i));
        }
        Console.WriteLine(ans);
    }
}