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: Accepted)

S = input()

ans = 0
if len(S) % 2 == 0:
    ans = len(S)//2
    c = ans
    t = S[ans]
    for i in range(len(S)//2-1,-1,-1):
        if S[i] == S[c] and S[i] == t:
            ans += 1
            c += 1
        else:
            break
else:
    ans = len(S)//2+1
    c = ans
    t = S[ans-1]
    for i in range(len(S)//2-1,-1,-1):
        if S[i] == S[c] and S[i] == t:
            ans += 1
            c += 1
        else:
            break


print(ans)