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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
#define ll long long
using namespace std;
inline int read()
{int x=0,f=0;
char c=getchar();
while (c<'0'||c>'9') 
{if (c=='-') f=1;
c=getchar();
}
while (c>='0'&&c<='9') x=x*10+c-'0',c=getchar();
if (f) x=-x;
return x;
}
char s[100005];
bool t[100005];
int main (){
	int i,len,ans=0;
	scanf ("%s",s+1);
	len=strlen(s+1);
	for (i=len;i>=1;i--)
	{if (s[i]==s[len]) {ans++;}
	}
	printf ("%d\n",max(ans,len+1-ans));
	return 0;
}