Like any decent web application, this game does not work on Internet Explorer.
The MoDELS'13 Game

Use the Model Explorer to query the secret MoDELS'13 model with EOL, answer the questions on the right and discover interesting facts about the conference!

Level 1 of 10

Let's start with the basics.

Copy and paste the solution below into the Model Explorer and click on the magnifying glass to reveal the answer.
// We'll give you this one
Paper.all.size().println();
package conference; 

class Conference { 
  attr String name; 
  attr int year; 
  val Track[*] tracks; 
  val Author[*] authors; 
} 

class Track { 
  attr String name; 
  val Paper[*]#track papers; 
} 

class Paper { 
  attr String title; 
  ref Author[*] authors; 
  ref Track#papers track; 
} 

class Author { 
  attr String name; 
  attr String affiliation; 
  attr String country; 
}