import java.util.*;

public class MultiSet<E> extends AbstractCollection<E> {

    private int count;
    private int tried;
    private int top;
    private int end;
    private Object[] set;

    public MultiSet() {
        this.set = new Object[50];
        this.count = 0;
        this.tried = 0;
        this.top = 0;
        this.end = 0;
    }

    public MultiSet(MultiSet m) {
        this.set = m.set;
        this.count = m.count;
        this.tried = m.tried;
        this.top = m.top;
        this.end = m.end;
    }

    public String toString() {
        String result = null;
        for(Object o: set) {
            result += o + " ";
        }
        return result;
    }

    public Iterator<E> iterator() {

        return new Iterator<E>() {
            public boolean hasNext() {
                return count > tried;
            }

            public E next() {
                int index = (top + tried) % set.length;
                E e = (E) set[index];
                tried++;
                return e;
            }

            public void remove() {
                throw new UnsupportedOperationException();
            }
        };

    }

    public E remove() {
        E e = (E) set[top];
        top = (top + 1) % set.length;
        count--;
        return e;
    }

    public boolean add(E e) {
        set[end] = e;
        end = (end + 1) % set.length;
        count++;
        return true;
    }
    public int size() {
        return this.count;
    }
}