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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <math.h>
#include <string.h>
#define max(a,b) ((a>b)?a:b)

int main(void){
    char s[100001];
    scanf("%s", s);
    int i;
    int count = strlen(s);
    int a[count+1];
    for(i=0;i<count;i++){
        if(s[i]=='0') a[i+1] = 0;
        if(s[i]=='1') a[i+1] = 1;
    }
    // printf("count = %d\n", count);
    // for(i=1;i<=count;i++) printf("%d", a[i]);
    int c_count = 1;
    int temp = 1;
    for(i=1;i<count;i++){
        if(a[i]==0&&a[i+1]==0) temp += 1;
        else temp = 1;
        c_count = max(c_count, temp);
    }
    if(c_count==1) printf("2");
    else printf("%d", c_count);
}