FF has

dogs numbered

. At the beginning, the dogs are arranged by their number in ascending order. They are playing a swapping game, the rules of game are as follows:
1. The dogs will swap in every second.
2. If the current number of seconds is odd, then swap the dog which index is

and
)
. For example, if

, the sequence of dogs is

and the current time at the beginning(current time is 1), then the dogs will be

after 1-st second.
3. If the current number of seconds is even, then swap the dog which index is

and
)
. For example, if

, the sequence of dogs is

and the current time is 2, then the dogs will be

after 2-nd seconds.
FF wants to know, what is the index of the dog numbered

after

seconds.