public class MyArrayCollection implements Collection<Integer> {
    final int CAPACITY = 9;
    protected int size;
    protected int [] array = new int[CAPACITY];

    public boolean add(Integer x) {
        if (size == CAPACITY) {
            return false;
        }
        else {
            array[size] = x;
            size++;
            return true;
        }
    }

    public boolean addAll(Collection<? extends Integer> c)  {
        if (size == CAPACITY) {
            return false;
        }
        else {
            for (Integer x: c) {
                if (size < CAPACITY) {
                    this.add(x);
                    size++;
                }
                else {
                    break;
                }
            }
        }
        return  true;
    }

    public void clear() {
        size = 0;
    }

    public boolean contains(Object o) {
        boolean pr = false;
        if (size == 0) {
            pr = false;
        }
        else {
            for (Object i : array) {
                if (i == o) {
                    pr = true;
                    break;
                }
            }
        }
        return pr;
    }

    public boolean containsAll(Collection<?> c) {
        boolean pr = true;
        if (size < c.size()) {
            pr = false;
        }
        else {
            for (Object x : c) {
                if (!this.contains(x)) {
                    pr = false;
                    break;
                }
            }
        }
        return pr;
    }

    public boolean equals(Object o) {
        return this.equals(o);
    }

    public int hashCode() {
        return 0;
    }

    public boolean isEmpty() {
        if (size == 0) {
            return true;
        } else {
            return false;
        }
    }

    public Iterator<Integer> iterator() {
        return null;
    }

    public boolean remove(Object o) {
        boolean pr = false;
        if (size == 0) {
            pr = false;
        }
        else {
            if (this.contains(o)) {
                size--;
                pr = true;
            }
        }
        return pr;
    }

    public boolean removeAll(Collection<?> c) {
        boolean pr = false;
        if (size == 0) {
            pr = false;
        }
        else {
            for (Object x: c) {
                if (this.contains(x)) {
                    this.remove(x);
                    size--;
                    pr = true;
                }
            }
        }
        return pr;
    }

    public boolean retainAll(Collection<?> c) {
        boolean pr = false;
        if (size == 0) {
            pr = false;
        }
        else {
            for (int i: this) {
                if (!c.contains(i)) {
                    this.remove(i);
                    size--;
                    pr = true;
                }
            }
        }
        return pr;
    }

    public int size() {
        return size;
    }

    public Object[] toArray() {
        return null;
    }

    public <T> T[] toArray(T[] a) {
        return null;
    }