//Dictionary//////////////////////////////////
function Dictionary()
{
	this.length = 0;
}
Dictionary.prototype.lookup = function(key)
{
	return(this[key]);
}
Dictionary.prototype.add = function(key, item)
{
	if (!this.exists(key)) this.length++;
	this[key] = item;
}
Dictionary.prototype.remove = function(key)
{
	this[key] = null;
	if (this.length > 0) this.length--;
}
Dictionary.prototype.exists = function(key)
{
	return this[key] != null;
}
/////////////////////////////////////////////////