Ren has recently created a website, Ternary Search, which he intends on turning into the premier platform
for competitive programmers to talk about anything.
Ren's website has become quite popular, and now has
users. The friendship graph is quite strange though,
the friendships form a structure where for any distinct two users
and
, there is a unique sequence of
distinct users
such that adjacent users in the sequence are friends.
Ren wants to create a team programming contest where there are exactly
teams that compete. There are
two constraints for teams - each team must contain at least one user (each user is on exactly one team),
and if two users are on the same team, they cannot have been friends to begin with.
Every user on the website will participate in this contest.
Let
be the number of distinct arrangements of
teams that can be formed. The teams are labeled, so
two arrangements of teams are considered distinct if there exists some user
that is on team
in one arrangement
and not on team
in the other arrangement.
Compute the median value of
over all possible friendship structures. Two friendship structures are different
if there are two users
and
who are friends in one structure but not friends in the other.
For the purposes of this problem, we define the median to be any integer
such that at most half the integers in the collection are larger than
and at most half the integers in the collection are smaller than
. This definition may not match conventional definitions of
median but is consistent with the formal definition of median. Note that this means that the median is not necessarily unique.
Constraints


Input Specification
The first and only line of input contains two space-separated integers,
and
.
Output Specification
Output the median modulo
. Note that you should be computing the median first and then taking it modulo
, as opposed to
taking the modulo of all values and computing the median of that collection.
Any valid median that respects the above definition will be accepted.
Sample Input
Copy
3 2
Sample Output
Copy
2
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