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: Accepted)

#include <bits/stdc++.h>
using namespace std;

string s;

int k = (int)1e5;

int main(void){
    // Here your code !
    cin >> s;
    int length = s.size();

    bool all1 = true;
    for (int i = 0; i < s.size(); ++i) {
      all1 &= (s[i] == '1');
    }
    if (all1) {
      printf("%d\n", length);
      return 0;
    }

    bool all0 = true;
    for (int i = 0; i < s.size(); ++i) {
      all0 &= (s[i] == '0');
    }
    if (all0) {
      printf("%d\n", length);
      return 0;
    }

    for (int i = 0; i < s.size() - 1; ++i) {
      if (s[i] != s[i + 1]) {
        int size = max(i + 1, length - (i + 1));
        k = min(k, size);
      }
    }

    printf("%d\n", k);

    return 0;
}