398. Friends of Friends
Time limit per test: 0.25
second(s)
Memory limit: 65536
kilobytes
input: standard
output: standard
Social networks are very popular now. They use different types of relationships to organize individual users in a network. In this problem friendship is used as a method to connect users. For each user you are given the list of his friends. Consider friendship as a symmetric relation, so if user
a is a friend of user
b then
b is a friend of
a.
A friend of a friend for
a is such a user
c that
c is not a friend of
a, but there is such
b that
b is a friend of
a and
c is a friend of
b. Obviously
c ≠
a.
Your task is to find the list of friends of friends for the given user
x.
Input
The first line of the input contains integer numbers
N and
x (1 ≤
N ≤ 50, 1 ≤
x ≤
N), where
N is the total number of users and
x is user to be processed. Users in the input are specified by their numbers, integers between 1 and
N inclusive. The following
N lines describe friends list of each user. The
ith line contains integer
d_{i} (0 ≤
d_{i} ≤ 50) — number of friends of the
ith user. After it there are
d_{i} distinct integers between 1 and
N — friends of the
ith user. The list doesn't contain
i. It is guaranteed that if user
a is a friend of user
b then
b is a friend of
a.
Output
You should output the number of friends of friends of
x in the first line. Second line should contain friends of friends of
x printed in the increasing order.
Example(s)
sample input

sample output

4 2
1 2
2 1 3
2 4 2
1 3

1
4

sample input

sample output

4 1
3 4 3 2
3 1 3 4
3 1 2 4
3 1 2 3

0
