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 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>
int min(int x,int y){return x>y?y:x;}
int max(int x,int y){return x>y?x:y;}
int main(void){
    char S[114514];
    scanf("%s",S);
    int ans=1;
    char maemoji=S[0];
    int count=1;
    for(int i=1;i<strlen(S);i++){
        if(S[i]!=maemoji){
            maemoji=S[i];
            ans=max(ans,min(i,strlen(S)-i+count));
            count=1;
        }
        else count++;
        if(i==strlen(S)-1)ans=max(ans,min(i+1,strlen(S)-(i+1)+count));
    }
    printf("%d",ans);
    return 0;
    
}