The number that remains

Given a sequence of consecutive natural numbers starting from n and ending at m (n < m), perform the following steps repeatedly until only one number remains:

1. Remove all numbers that are in odd positions. 2. From the remaining numbers, remove all numbers that are in even positions.

Your task is to write a program that determines the last remaining number.

Input

The input consists of two lines: the first line contains the integer n, and the second line contains the integer m, where n < m < 1000000000.

Output

Output the last remaining number.

Examples