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: Accepted)

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair <int,int> pa;
const int N = 2e5+100;
char s[N];
int ans;
void solve()
{
   cin>>s+1;
   int len=strlen(s+1);
  // cout<<len<<endl;
   ans=len/2;
   while(1){
     int l=len-ans+1,r=ans;
     for(int i=l;i<r;i++)
        if((s[i]-'0')^(s[i+1]-'0')) return ;
        ans++;
   // if(ans==len) break;
   }
}
int main()
{
    ios::sync_with_stdio(0);cin.tie(0);
    solve();
    cout<<ans-1<<endl;
    return 0;
}