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: Wrong Answer)

#include <stdio.h>
#include <string.h>


void sort(char data[], long left, long right)
{
	long sample = data[left], lptr = left, rptr = right;
	if (lptr < rptr){
		while (lptr != rptr){
			while ((sample > data[rptr]) && (lptr != rptr)) rptr--;
			if (lptr != rptr) data[lptr++] = data[rptr];
			while ((data[lptr] > sample) && (lptr != rptr)) lptr++;
			if (lptr != rptr) data[rptr--] = data[lptr];
		}
		data[lptr] = sample;
		sort(data, left, lptr - 1);
		sort(data, rptr + 1, right);
	}
}
int countlonger(char s[])
{
	int cnt = 0;
	while (cnt < strlen(s)){
		if (s[cnt] == '0') break;
		else cnt++;
	}
	return (cnt > strlen(s) - cnt) ? cnt : strlen(s) - cnt;
}
int main(void)
{
	char s[1000001];
	scanf("%s", s);
	sort(s,0,strlen(s)-1);
	printf("%d\n", countlonger(s));
	return 0;
}