Lately, the koalas have noticed that their feeding grounds are too far away from their home so they have decided to find a better way to move between their destinations. Lucky for them, you have a bunch of teleporters lying around, so they hire you to fix their problem!
The koalas live in a forest of
connected trees, numbered from
to
, joined by
branches that can be crossed in either direction in
minute; each tree is a possible feeding ground. The koalas' home is tree
. On each of the next
days, the koalas will have a new set of
distinct feeding grounds, with the
feeding ground designated as
.
A teleportation plan for the koalas will be built daily. To do so, we will first choose any tree
. Then, on all the trees on the unique simple path from tree
to tree
, we will install a teleporter; a teleporter allows for instant travel to any other teleporter. Note that teleporters only last for one day and a plan must be redesigned every day.
Each day, koalas populate all feeding grounds designated for that day, and every evening, all koalas need to return home. Among all possible teleportation plans, you are to find one that allows all the koalas to return to tree
using the minimum total time
and report this number to the chief koala!
For this problem, Python users are recommended to use PyPy over CPython.
Constraints
For this problem, you will NOT be required to pass the sample cases in order to receive points.



For each day, all
are distinct.
The sum of
over all days is guaranteed to be less than or equal to
.
Subtask 1 [5%]

Subtask 2 [15%]

Subtask 3 [80%]
No additional constraints.
Input Specification
The first line contains two space-separated integers
and
.
The next
lines each contain 2 integers
and
, indicating a bidirectional branch between trees
and
.
lines follow, with
lines for each day. The first line for each day contains
, followed by
integers
on the next line, representing the designated feeding grounds for day
.
Output Specification
Output
lines, the
of which contains the minimum time
for the
day.
Sample Input 1
Copy
6 2
1 2
2 3
1 4
4 5
2 6
3
3 5 6
3
1 2 6
Sample Output 1
Copy
3
0
Explanation for Sample 1
For the first day, the optimal
is
, and the teleporters will be installed on trees
,
, and
. Since tree
is already on the path, its distance is
. Tree
is
branch away from its closest teleporter (tree
) and tree
is
branches away from its closest teleporter at tree
. Therefore the answer is
minutes.
For the second day, we again choose
. Since teleporters are installed on all feeding grounds, the answer is
.
Sample Input 2
Copy
6 2
5 1
1 6
6 3
3 4
4 2
2
5 6
3
1 2 3
Sample Output 2
Copy
1
0
Comments