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++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <algorithm>
#include <iomanip>
#include <string>
#include <vector>
#include <math.h>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#define PI 3.14159265359
typedef long long ll;
const int MOD = 1e9+7;
const ll LLINF = 1e18;
using namespace std;


int main(){
	string s;
	cin >> s;
	int ans = MOD;
	for (int i = 0; i < s.length()-1; i++){
		if (s[i] != s[i+1]){
			int temp = max(i+1, (int)s.length()-i-1);
			ans = min(temp, ans);
		}
	}
	cout << ans << endl;
	return 0;
}