using System;
using System.Collections;

class App{

 public static void Main(){
   StringSet s1 = new StringSet(),
             s2 = new StringSet();

   s1.Insert("a"); s1.Insert("b");  s1.Insert("c");
   s1.Insert("dd"); s1.Insert("ee");  s1.Insert("ff");
   s1.Insert("ggg"); s1.Insert("hhh");  s1.Insert("iii");
   s1.Delete("c"); s1.Delete("ff");  s1.Insert("iii");

   s2.Insert("a"); s2.Insert("iii"); 

   Console.WriteLine("s1: {0}", s1);
   Console.WriteLine("s2: {0}", s2);

// Exercises:
// Console.WriteLine("{0}", s2.Intersection(s1));
// Console.WriteLine("{0}", s2.Union(s1));
// Console.WriteLine("{0}", s2.Diff(s1));

   if (s1.Subset(s2))
     Console.WriteLine("s1 is a subset of s2");
   else 
     Console.WriteLine("s1 is not a subset of s2");

   if (s2.Subset(s1))
     Console.WriteLine("s2 is a subset of s1");
   else 
     Console.WriteLine("s2 is not a subset of s1");
 }
}