class PeopleFilter
{

PersonChoose myChoose;

 public PeopleFilter(PersonChoose chooser)
 {
  myChoose=chooser;
 }

 public int filter(Person [] a,int n)
 {
  int count=0;
  for(int i=0;i<n;i++)
     if(myChoose.choose(a[i]))
        a[count++]=a[i];
  return count;
 }

}