import java.util.*;

class IntSet8 
{
// Constructive sets represented as arrays of integers
// Includes union and intersection methods that use method 'add'

 private int[] array;

 public IntSet8()
 {
  array = new int[0];
 }

 private IntSet8(int[] a)
 {
  array = a;
 }

 public IntSet8 delete(int n)
 {
  int i;
  for(i=0; i<array.length&&array[i]<n; i++) {}
  if(i<array.length&&array[i]==n)
     {
      int[] array1 = new int[array.length-1];
      for(int j=0; j<i; j++)
         array1[j]=array[j];
      for(i++;i<array.length; i++)
         array1[i-1]=array[i];
      return new IntSet8(array1);
     }
  return this;
 }

 public IntSet8 add(int n)
 {
  int i;
  for(i=0; i<array.length&&array[i]<n; i++) {}
  if(i==array.length||array[i]>n)
     {
      int[] array1 = new int[array.length+1];
      for(int j=0; j<i; j++)
         array1[j]=array[j];
      array1[i]=n;
      for(int j=array.length; j>i; j--)
         array1[j]=array[j-1];
      return new IntSet8(array1);
     }
  return this;
 }

 public boolean member(int n)
 {
  int from=0, to=array.length;
  int mid=(from+to)/2;
  while(from!=to&&array[mid]!=n)
     {
      if(array[mid]>n)
         to=mid;
      else
         from=mid+1;
      mid=(from+to)/2;
     }
  return from!=to;
 }

 public String toString()
 {
  int i;
  String str="{";
  if(array.length>0)
     {
      str+=array[0];
      for(i=1;i<array.length;i++)
         str+=","+array[i];
     }
  return str+"}";
 }

 public static IntSet8 fromString(String str) 
 {
  IntSet8 set = new IntSet8();
  str=str.trim();
  if(str.charAt(0)!='{'||str.charAt(str.length()-1)!='}')
     return new IntSet8();
  str = str.substring(1,str.length()-1);
  StringTokenizer toks = new StringTokenizer(str,",");
  try {
       while(toks.hasMoreTokens())
          {
           String num = toks.nextToken().trim();
           set=set.add(Integer.parseInt(num));
          }
       return set;
      }
  catch(NumberFormatException e)
      {
       return new IntSet8();
      }
 }

 public IntSet8 union(IntSet8 set)
 {
  for(int i=0; i<array.length; i++)
     set = set.add(array[i]);
  return set;
 }

 public IntSet8 intersection(IntSet8 set)
 {
  IntSet8 newSet = new IntSet8();
  for(int i=0; i<array.length; i++)
     if(set.member(array[i]))
        newSet = newSet.add(array[i]);
  return newSet;
 }
}