Let an integer n be given. Write the integers from 1 to n in binary notation successively from left to right. In the resulting string consisting of zeros and ones, choose a palindrome substring of maximal length. It is required to find the length of this substring.

The only input line contains the integer n in binary notation (1 ≤ n ≤ 2^1 000 000).

Output one line containing the required length.

In the first sample, the string 11011100101 will be written (a variant of the longest palindrome is underlined).