ACMSGURU 398  Friends of Friends
Friends of Friends
Problem Description
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 di (0 ≤ di ≤ 50) — number of friends of the ith user. After it there are di 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 
Solution
1 
