class IntSet3
{
// Set class, sets stored as ordered partly-filled arrays

 private int[] array;
 private int count;
 final static int MAX=100;

 public IntSet3()
 {
  array = new int[MAX];
 }

 public void delete(int n)
 {
  int i;
  for(i=0; i<count&&array[i]<n; i++) {}
  if(i<count&&array[i]==n)
     {
      for(;i<count; i++)
         array[i]=array[i+1];
      count--;
     }
 }

 public void add(int n)
 {
  int i;
  for(i=0; i<count&&array[i]<n; i++) {}
  if(i==count||array[i]>n)
     {
      for(int j=count; j>i; j--)
         array[j]=array[j-1];
      array[i]=n;
      count++;
     }
 }

 public boolean member(int n)
 {
  int from=0, to=count;
  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(count>0)
     {
      str+=array[0];
      for(i=1;i<count;i++)
         str+=","+array[i];
     }
  return str+"}";
 }
}