ONLY ONE NUMBER LEFT

Petryk Pyatochkin has decided to remove all odd numbers and numbers at odd positions from a sequence of natural numbers ranging from 1 to N. He starts by eliminating all odd numbers, followed by numbers at odd positions, and continues this process until only one number is left. What is this final number?

Input

A natural number N (N=2…2^63).

Output

The last remaining number.

Examples