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-----
010

-----Sample Output-----
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.

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