import java.util.*;

class IntSet10
{
 // Implementation of set of integers using array of booleans
 // Integers restricted to range 0 to MAX-1
 // Uses constructive methods, including union and intersection

 private boolean[] array;
 public static final int MAX=100;
 
 public IntSet10()
 {
  array = new boolean[MAX];
 }

 private IntSet10(boolean[] a)
 {
  array=a;
 }

 public IntSet10 delete(int n)
 {
  if(array[n])
     {
      int i;
      boolean[] a = new boolean[MAX];
      for(i=0;i<n;i++)
         a[i]=array[i];
      a[i++]=false;
      for(;i<MAX;i++)
         a[i]=array[i];
      return new IntSet10(a);
     }
  else
     return this;
 }

 public IntSet10 add(int n)
 {
  if(!array[n])
     {
      int i;
      boolean[] a = new boolean[MAX];
      for(i=0;i<n;i++)
         a[i]=array[i];
      a[i++]=true;
      for(;i<MAX;i++)
         a[i]=array[i];
      return new IntSet10(a);
     }
  else
     return this;
 }

 public boolean member(int n)
 {
  return array[n];
 }

 public String toString()
 {
  String str="{";
  int i;
  for(i=0; i<MAX&&!array[i]; i++) {}
  if(i<MAX)
     {
      str=str+i;
      for(i++;i<MAX;i++)
         if(array[i])
            str+=","+i;
     }
  return str+"}";
 }
 
 public static IntSet10 fromString(String str)
 {
  boolean[] a = new boolean[MAX];
  str=str.trim();
  if(str.charAt(0)!='{'||str.charAt(str.length()-1)!='}')
     return new IntSet10(a);
  str = str.substring(1,str.length()-1);
  StringTokenizer toks = new StringTokenizer(str,",");
  try {
       while(toks.hasMoreTokens())
          {
           String num = toks.nextToken().trim();
           a[Integer.parseInt(num)]=true;
          }
      }
  catch(NumberFormatException e)
      {
       for(int i=0; i<MAX; i++)
          a[i]=false;
      }
  return new IntSet10(a);
 }

 public IntSet10 union(IntSet10 set)
 {
  boolean[] a = new boolean[MAX];
  for(int i=0; i<MAX; i++)
     a[i]=this.array[i]||set.array[i];
  return new IntSet10(a);
 }

 public IntSet10 intersection(IntSet10 set)
 {
  boolean[] a = new boolean[MAX];
  for(int i=0; i<MAX; i++)
     a[i]=this.array[i]&&set.array[i];
  return new IntSet10(a);
 }
}