It is recently discovered that someone in

's school has contracted Ebola (an extremely dangerous viral disease). The school administrators were frightened that more people would become infected and decided to isolate those who are potentially infected. They reached out to to help them resolve their dilemma.There are a total of people in 's school, numbered to . There are a total of classes, and the 'th class has a size of . Each person can be part of or more classes. Initially, the person numbered is infected with Ebola.

A person is deemed potentially infected if:

- The person is already infected
- The person has class with the infected person
- The person has class with someone that is potentially infected

Please write a program to help

determine who is potentially infected.#### Constraints

##### Subtask 1 [80%]

##### Subtask 2 [20%]

For all testcases, .

#### Input Specification

On the first line of the input are 2 integers and .

This line is followed by lines which describes each class.

Every line begins with an integer (), which represents the number of students in that class. integers follows, indicating the number of people in the 'th class.

#### Output Specification

Output the number of potentially infected people on the first line of the output.

On the second line, please output the sorted list of potentially infected people, separated by a space.

#### Sample Input

```
9 4
3 1 2 3
4 2 3 4 5
3 6 7 8
2 3 9
```

#### Sample Output

```
6
1 2 3 4 5 9
```

## Comments

2020: hold my corona

HelpI don't understand what I am missing for an AC. Can someone please help.

is 1 always going to be the second number on line 2?

No, it is not. The person numbered can be part of any group, or no group at all.

Is there a smaller restriction on the size of K? I don't think it's even possible to input 10^5^2 = 10^10 things in 0.5s.

Edit: read the comment wrong.

Since processing takes linear time, having would be insane.

It should be . The problem statement has been corrected.

Ebola isn't spread by being near someone who has it. Ebola is spread through direct contact with blood or bodily fluids from someone who has or died with Ebola.

virus is a noun viral is the adjective pls don't disqualify me

Nice catch! The wording has been corrected.