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)

#pragma GCC optimize("O3")
#include<bits/stdc++.h>
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define in insert
#define er erase
#define fr first
#define sc second
using namespace std;
typedef long long ll;
const long long llnrm=LLONG_MAX;
const int nrm=INT_MAX;
const int nrn=INT_MIN;
const int nmax=1e5+5;
const int mod=1e9+7;
const int lim=1e8;
int main(){
	string x;
	int ans0=0,ans1=0,b;
	cin>>x;
	b=x.size();
	for (int k=0; k<b; k++){
	    if (x[k]=='0'){
	        ans0++;
	    }
	    if (x[k]=='1'){
	        ans1++;
	    }
	}
	cout<<max(ans0,ans1);
}