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 Python (3.4.3) (judge verdict: Wrong Answer)

S = list(map(int, list(input())))

zero = 1000000
one = 1000000
current_zero = 0
current_one = 0

for i in range(len(S)- 1):
	if S[i] == 0:
		current_zero += 1
	else:
		current_one += 1
	if S[i] != S[i+1]:
		if S[i] == 0 and current_zero < zero:
			zero = current_zero
		elif S[i] == 1 and current_one < one:
			one = current_one
		current_zero = 0
		current_one = 0
	elif i == len(S) - 2:
		if S[i] == 0:
			current_zero += 1
			if current_zero < zero:
				zero = current_zero
		else:
			current_one += 1
			if current_one < one:
				one = current_one
#print(zero, one)
print(max(2, max(zero, one)))