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 <stdlib.h>
#include <string.h>
#include <math.h>

int descending_compare(const void *a, const void *b){
    return (int)(*(int*)b - *(int*)a);
}

int ascending_compare(const void *a, const void *b){
    return (int)*(int*)a - *(int*)b;
}

char input[100005];

int main(void){
    int i;
    int answer = 100005;
    for (i = 0; i < 100005; i++){
        input[i] = 'a';
    }
    scanf("%s", input);
    int len = strlen(input);
    for (i = 0; i < len; i++){
        if (input[i] != input[i+1]){
            if (answer > (i+1>len-(i+1)?i+1:len-(i+1))){
                answer = i+1>len-(i+1)?i+1:len-(i+1);
            }
        }
    }


    printf("%d\n", answer);



    return 0;
}