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: Wrong Answer)

#include <stdio.h>
#include <string.h>
#include <stdbool.h>
int max(int a,int b){return a>b?a:b;}
int main(void){
    int ans=1,count=1,prev=0;
    char s[100020];
    bool flag1=false,flag2=false;
    scanf("%s",s);
    for (int i=1; i<strlen(s); i++){
        if (s[i]==s[i-1]){
            count++;
        } else {
            if (flag1==false){
                ans=max(ans,count);
                count=1;
                flag1=true;
            } else if (flag2==false){
                ans=max(ans,count);
                prev=count;
                count=1;
                flag2=true;
            } else {
                ans=max(ans,count+prev);
                prev=count;
                count=1;
            }
        }
    }
    printf("%d\n",max(ans,count));
    return 0;
}