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 <stdlib.h>
#include <string.h>
int fw(const void *a, const void *b)
{
	return *(int*)a - *(int*)b;
}
int bw(const void *a, const void *b)
{
	return *(int*)b - *(int*)a;
}
//qsort(vector, n, sizeof(int), fw);
int main() {
	char s[100010] = {}, cl, cr;
	int ans, l, r, len;
	scanf("%s", s);
	len = strlen(s);
	printf("%d\n", len);
	cl = s[0]; cr = s[len - 1];
	for (l = 0; s[l] == cl; l++) {}
	for (; s[l] != cl && l < len-1; l++) {}

	for (r = 0; s[len-r-1] == cr; r++) {}
	for (; s[len-r-1] != cr && r < len-1; r++) {}

	ans = (l > r) ? l : r;
	printf("%d", ans);
	return 0;
}