Problem:
Score : 500 points

Problem Statement

You are given a string S consisting of 0 and 1.
Find the maximum integer K not greater than |S| such that we can turn all the characters of S into 0 by repeating the following operation some number of times.

Choose a contiguous segment [l,r] in S whose length is at least K (that is, r-l+1\geq K must be satisfied). For each integer i such that l\leq i\leq r, do the following: if S_i is 0, replace it with 1; if S_i is 1, replace it with 0.

Constraints

1\leq |S|\leq 10^5

S_i(1\leq i\leq N) is either 0 or 1.

Input

Input is given from Standard Input in the following format:

S

Output

Print the maximum integer K such that we can turn all the characters of S into 0 by repeating the operation some number of times.

Sample Input 1

010

Sample Output 1

2

We can turn all the characters of S into 0 by the following operations:

Perform the operation on the segment S[1,3] with length 3. S is now 101.

Perform the operation on the segment S[1,2] with length 2. S is now 011.

Perform the operation on the segment S[2,3] with length 2. S is now 000.

Sample Input 2

100000000

Sample Output 2

8

Sample Input 3

00001111

Sample Output 3

4

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
class Program
{
    private bool check(int[] s, int k)
    {
        return (s[k] != s[k + 1]) ? true : false;
    }
    public static void Main()
    {
        Program prog = new Program();
        string str = Console.ReadLine();
        int[] s = new int[str.Length];
        for (int i = 0; i < str.Length; i++)
            s[i] = (int)Char.GetNumericValue(str[i]);
        int t = str.Length;
        if (str.Length > 1)
        {
            for (int j = 0; j < str.Length - 1; j++)
            {
                if (prog.check(s, j))
                    if (Math.Max(j + 1, str.Length - j - 1) < t)
                        t = Math.Max(j + 1, str.Length - j - 1);
            }
        }
        else
            t = 1;
        Console.WriteLine(t);
    }
}