void insert(x) {
	// insert element
	array[heapSize] = x; 
	heapSize++; 
	// recover BT
	siftUp(heapSize-1); 
}

int extractMin() {
	swap(array[0], array[heapSize-1]); 
	int hold = array[heapSize-1]; 
	delete array[heapSize-1]; 
	// recover BT
	siftDown(0); 
	
	return hold;
}

int min() {
	return array[0]; 
}