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 <stdio.h>
#include <iostream>
#include <vector>
#include <math.h>
#include <algorithm>
#include <functional>
using namespace std;
//#define rep(i,n) for(i=0; i < n; i++)
typedef long long ll;
#define MAX 10000000

vector<int> V(MAX);


int main(){
    string s;
    cin >> s;
    //0の最大距離を求める
    int len = s.length();
    int minl = MAX;
    for(int i = 0; i < s.length()-1; i++){
        if(s[i]!=s[i+1]) {
            int tmp = max(i+1, len-(i+1));
            if(minl > tmp) minl = tmp;
        }
    }
    cout << minl << endl;
}