Description

Being a nonconformist, Volodya is displeased with the current state of things, particularly with the order of natural numbers (natural number is positive integer number). He is determined to rearrange them. But there are too many natural numbers, so Volodya decided to start with the firstn. He writes down the following sequence of numbers: firstly all odd integers from1ton(in ascending order), then all even integers from1ton(also in ascending order). Help our hero to find out which number will stand at the position numberk.

Format

Input

The only line of input contains integersnandk(1 ≤k≤n≤ 10^12).

Output

Print the number that will stand at the position numberkafter Volodya's manipulations.

Samples

10 3
7 7

5
6

Hint

In the first sample Volodya's sequence will look like this: {1, 3, 5, 7,

9, 2, 4, 6, 8, 10}. The third place in the sequence is therefore

occupied by the number 5.