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 Perl (v5.18.2) (judge verdict: Accepted)

$S=<STDIN>;chomp $S;

$L=length($S);

if($L % 2==0) {
	$r=$L/2;
	$i=int($L/2);$j=1;
	$c=substr($S,$i,1);
	while ( $r<$L && substr($S, $i-$j,1) eq $c && substr($S,$i+$j-1,1) eq $c ) {
		$j+=1;
		$r+=1;
	}
} else {
	$r=($L+1)/2;
	$i=int($L/2);$j=1;
	$c=substr($S,$i,1);
	while ( $r<$L && substr($S, $i-$j,1) eq $c && substr($S,$i+$j,1) eq $c ) {
		$j+=1;
		$r+=1;
	}
}
print $r;