class Node:
    def __init__(self, data, p):
        self.next: Node = None
        self.prev: Node  = None
        self.data = data
        self.prio = p

    def get_priority(self):
        return self.prio

    def get_data(self):
        return self.data

    def set_next(self, next):
        self.next = next

    def set_prev(self, prev):
        self.prev = prev

    def get_next(self):
        return self.next

    def get_prev(self):
        return self.prev

class PriorityQueue:
    def __init__(self):
        self.head = None
        self.tail = None
        self.size = 0

    def get_size(self):
        return self.size

    def is_empty(self):
        return self.head == None

    def push(self, data, p):
        new_element: Node = Node(data, p)
        probe: Node = self.head

        if self.is_empty():
            self.head = new_element
            self.tail = self.head

            self.size += 1
            return

        # hledam neco s nizsi prioritou
        while probe.get_next() is not None:
            # a pokud to najdu pripojim pred nej
            if p >= probe.get_priority():
                probe.set_prev(new_element)
                new_element.set_next(probe)

                self.size += 1
                return

        # nenasel jsem prvek s nizsi prioritou, novy dam na konec
        self.tail.set_next(new_element)
        new_element.set_prev(self.tail)
        self.tail = new_element