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)


  //In The Name Of GOD

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
const ll mod = 998244353;
const ll inf = 2000000000;
const ll infll = (ll)2*1000*1000*1000*1000*1000*1000;
const ll maxn = 100*1000+1;
#define pb push_back
#define pp pop_back
#define X first
#define Y second
#define IO ios_base::sync_with_stdio(false);

int main(){
  IO;
  string s;
  int ans=0;
  cin>>s;
  for(int i=0;i<s.size();i++){
    ans+=s[i]-'0';
  }
  cout<<max((int)s.size()-ans, ans);
}