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>
int MAX(int a,int b){return a<b?b:a;}
int MIN(int a,int b){return a<b?a:b;}
int main(){
  int i,l,ans,max=0,min=1e9,c=1,r=0,d[100010];
  char s[100010];
  scanf("%s",s);
  for(l=0;s[l];l++){
    if(s[l]==s[l+1])c++;
    else{
      d[r++]=c;
      c=1;
    }
  }
  max=(l+1)/2;
  for(i=1;i<r;i++)min=MIN(d[i-1]+d[i],min);
  max=MAX(max,min);
  if(r==2)max=MAX(d[0],d[1]);
  printf("%d\n",max);
  return 0;
}