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 Ruby (2.3.3) (judge verdict: Wrong Answer)

# Your code here!
n=gets.split("").map(&:to_i)
ll=n.length

ans=0
ren=0
if ll==1
    puts 1
exit
end


if n[0]==0 && n[1]==0
    ren=2
    ans=2
    one=0
    zero=2
    
elsif n[0]==1 && n[1]==1
   ren=2
    ans=2
    one=2
    zero=0

else 
    ans=1
    ren=1
    one=1
    zero=1
end

j=2
(ll-2).times{
   if n[j-1]!=n[j]   && n[j]==1
       ans+=1
       ren=1
       one+=1
       
   elsif  n[j-1]!=n[j]   && n[j]==0
       ans+=1
       ren=1
       zero+=1
       
    elsif   n[j-1]==n[j]   && n[j]==0 && ren+1>ans
    ans+=1
    ren+=1
    zero+=1
       if one==0
           ans-=1
        end
    
    elsif   n[j-1]==n[j]   && n[j]==0
    ren+=1
    zero+=1
    
    
        if one==0
           ans-=1
        end
    
    elsif   n[j-1]==n[j]   && n[j]==1 && ren+1>ans
    ans+=1
    ren+=1
    one+=1
         if zero==0
           ans-=1
        end
    elsif   n[j-1]==n[j]   && n[j]==1
    ren+=1
    one+=1
    
        if zero==0
           ans-=1
        end
end
      
   
   j+=1 
    
    
}

p ans