void sort()
{
	Kafedra * current = head;
	Kafedra* prev = 0;
	Kafedra* tempNode = 0;
	bool changeFlag = false;
	for (int i = 0; i < n; i++)
	{
		while (current->next != 0)
		{
			tempNode = current->next;

			if (current->count_of_students > tempNode->count_of_students)
			{
				changeFlag = true;
				current->next = tempNode->next;
				tempNode->next = current;
				if (prev != 0)
					prev->next = tempNode;
				prev = tempNode;
				if (head == current)
					head = tempNode;
				if (current->next == 0)
					tail = current;
			}
			else
			{
				prev = current;
				current = current->next;
			}
		}
		if (changeFlag == false)
			break;
		else
		{
			prev = 0;
			current = head;
			changeFlag = false;
		}
	}
}