class IntSet4
{
 // Implementation of set of integers using array of booleans
 // Integers restricted to range 0 to MAX-1

 private boolean[] array;
 public static final int MAX=100;
 
 public IntSet4()
 {
  array = new boolean[MAX];
 }

 public void delete(int n)
 {
  array[n]=false;
 }

 public void add(int n)
 {
  array[n]=true;
 }

 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+"}";
 }
}