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>

#define pb push_back
#define eb emplace_back

typedef long long ll;
typedef unsigned long long ull;

using namespace std;






void one_case() {
    string s;
    cin >> s;
    int best = s.size();
    for (int k = 1; k < s.size(); ++k) {
        if (s[k] != s[k - 1]) {
            best = min(best, max(k, int(s.size()) - k));
        }
    }
    cout << best << '\n';
}


int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);


    int t = 1;
//    cin >> t;
    while (t--) {
        one_case();
    }

    return 0;
}