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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;

/*
	01010
 */
public class Main
{
	public static void main (String[] args) throws Exception {
		Scanner in = new Scanner(System.in);
		String s = in.next();
		//int ans = Math.min(solve(s), solve(reverse(s)));
		//
		
		char[] arr = s.toCharArray();
		int cnt0 = 0;
		int cnt1 = 0;
		for(char c : arr) {
			if(c == '0')
				++cnt0;
			else 
				++cnt1;
		}
		System.out.println(Math.max(solve(arr), solve(reverse(s).toCharArray())));
 	}


 	private static int solve(char[] arr) {
 		
 		int mod = 0;
 		int cnt0 = arr[0] == '0' ? 1 : 0;
 		int cnt1 = arr[0] == '1' ? 1 : 0;
 		int ans = Integer.MAX_VALUE;
 		for(int i = 1; i < arr.length; ++i) {
 			if(arr[i] != arr[i - 1]) {
 				++mod;
 				if(mod >= 2) {
 					ans = Math.min(ans, cnt0 + cnt1);
 					if(arr[i] == '0')
 						cnt0 = 1;
 					else 
 						cnt1 = 1;
 				} else {
 					if(arr[i] == '0')
 						++cnt0;
 					else 
 						++cnt1;
 				}
 			} else {
 				if(arr[i] == '0')
 					++cnt0;
 				else 
 					++cnt1;
 			}
 		}

 		if(mod >= 2) {
 			return Math.min(ans, cnt0 + cnt1);
 		}

 		cnt0 = cnt1 = 0;

 		for(char c : arr) {
 			if(c == '0')
 				++cnt0;
 			else 
 				++cnt1;
 		}

 		return Math.max(cnt0, cnt1);

 	}


 	private static String reverse(String s) {
 		StringBuilder ret = new StringBuilder();
 		char[] arr = s.toCharArray();

 		for(char c : arr) {
 			if(c == '0')
 				ret.append('1');
 			else 
 				ret.append('0');
 		}

 		return ret.toString();
 	}

}