using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
class Program
{
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var s = ReadLine();

        var pal = new bool[s.Length, s.Length + 1];
        for (var i = 0; i < s.Length; ++i)
        {
            var d = 0;
            while (i - d >= 0 && i + d < s.Length && s[i - d] == s[i + d])
            {
                pal[i - d, i + d + 1] = true;
                ++d;
            }
        }
        for (var i = 0; i + 1 < s.Length; ++i)
        {
            var d = 0;
            while (i - d >= 0 && i + d + 1 < s.Length && s[i - d] == s[i + d + 1])
            {
                pal[i - d, i + d + 2] = true;
                ++d;
            }
        }
        var dp = new int[s.Length + 1];
        for (var i = 1; i <= s.Length; ++i) if (pal[0, i]) dp[i] = i;
        for (var i = 0; i < s.Length; ++i) for (var j = i + 1; j < dp.Length; ++j)
        {
            if (pal[i, j]) dp[j] = Math.Max(dp[j], Math.Min(dp[i], j - i));
        }
        WriteLine(dp[s.Length]);
    }
}