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<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#include<cstring>
#include<vector>
#include<cmath>
#include<queue>
#include<stack>
using namespace std;
#define INT(x) int x; scanf("%d",&x)
#define LL(x) ll x; scanf("%lld",&x)
#define INPUT(x) cin >> x
#define REP1(x,n) for(int x = 0; x < n; x++)
#define REP2(x,s,e) for(int x = s; x <= e; x++)
#define RREP1(x,n) for(int x = n-1; x >= 0; x--)
#define RREP2(x,s,e) for(int x = s; x >= e; x--)
#define BR printf("\n")
#define INF_INT 2147483647
#define INF_LL 9223372036854775807

typedef long long ll;

int main(){
    string s;
    cin >> s;
    
    int mini = 1000000;
    
    REP1(i, s.size()-1){
        if (s[i] != s[i+1]) {
            mini = min(mini, max(i+1, int(s.size()-1-i) ));
        }
    }
    
    cout << mini << endl;
    
    return 0;
}