operation Family getTitle() : String{
	return "Family";
}

operation Person getTitle() : String{
	return "Children of " + self.name;
}
	

operation Family getNumberOfMen() : String {
	return self.getMembers().select(m|m.isTypeOf(Man)).size.toString();
}

operation Person getNumberOfMen() : String {
	return self.getChildren().select(m|m.isTypeOf(Man)).size.toString();
}

operation Family getNumberOfWomen() : String {
	return self.getMembers().select(m|m.isTypeOf(Woman)).size.toString();
}

operation Person getNumberOfWomen() : String {
	return self.getChildren().select(m|m.isTypeOf(Woman)).size.toString();
}