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 PyPy3 (2.4.0) (judge verdict: Wrong Answer)

s = input() + '.'

count = []
pre = s[0]
c = 1
for t in s[1:] :
    if t == pre :
        c += 1
    else :
        count.append(c)
        pre = t
        c = 1

if len(count) == 1 and s[0] == '0' :
    print(0)
elif len(count) == 1 and s[0] == '1' :
    print(1)
elif len(count) % 2 == 1 :
    print(min([count[i] + count[i+1] for i in range(len(count)-1)]))
else :
    count_ = [count[0]] + [count[i] + count[i+1] for i in range(len(count)-1)] + [count[-1]]
    print(max(min(count_[1:]), min(count_[:-1])))