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 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
int main()
{
	char s[100005];
	scanf("%s", s);
	int i, n = strlen(s);
	int a[100005];
	a[0] = 0;
	for (i = 1; i < n; i++)
	{
		if (s[i] == s[i - 1])
			a[i] = a[i - 1];
		else
			a[i] = i;
	}
	int ans = 1;
	for (i = 0; i < n; i++)
	{
		if (n - a[i] >= i + 1 && ans < i + 1)
			ans = i + 1;
	}
	a[n - 1] = n - 1;
	for (i = n - 2; i >= 0; i--)
	{
		if (s[i] == s[i + 1])
			a[i] = a[i + 1];
		else
			a[i] = i;
	}
	for (i = 0; i < n; i++)
	{
		if (a[i] + 1 >= n - i && ans < n - i)
			ans = n - i;
	}
	printf("%d\n", ans);
	return 0;
}