class List {
private:

  class Node {
  public:
    int data;
    Node * next;
    Node (int data, Node *next) {
      Node::data = data; Node::next = next;
    }
  };

  Node *head;

public:

  // default contstructor: creates empty list
  List () { head = NULL; };

  // destructor: destroys list
  ~List ();

  // outputs list contents to cout
  void outputList () const;

  // adds a value at the beginning of the list
  void insert (int value);

  // Method "countOddValues" returns the number of nodes in the list containing odd values.
  // Note that "containing" refers to the *contents* of the node, not its position in the list.
  // If the list contains no odd values, it returns 0.
  int countOddValues() const;

  // Method "deleteValuesMultThree" deletes every node containing
  // a value that is an exact multiple of 3 (i.e. ..., -9, -6, -3, 0, 3, 6, ...). 
  // If the list contains no values that are multiples of 3, it has no effect.
  void deleteValuesMultThree(); 

};