class Node:
    def __init__(self, val):
        self.val = val
        self.next = None


class MyLinkedList:
    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.head = None

    def get(self, index):
        """
        Get the value of the index-th node in the linked list. If the index is invalid, return -1.
        :type index: int
        :rtype: int
        """
        cur = self.head

        while index:
            if index == 0 and cur:
                return cur.val
            index -= 1

            if cur:  # if cur then go cur.next
                cur = cur.next
            else:  # cur is None then the index is invalid
                return -1

    def addAtHead(self, val):
        """
        Add a node of value val before the first element of the linked list. After the insertion, the new node will be the first node of the linked list.
        :type val: int
        :rtype: void
        """
        new_head = Node(val)
        new_head.next = self.head
        self.head = new_head

    def addAtTail(self, val):
        """
        Append a node of value val to the last element of the linked list.
        :type val: int
        :rtype: void
        """
        cur = self.head
        if cur:  # non-empty linked list
            while cur.next:
                cur = cur.next
            cur.next = Node(val)
        else:  # empty linked list
            self.head = Node(val)

    def addAtIndex(self, index, val):
        """
        Add a node of value val before the index-th node in the linked list. If index equals to the length of linked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted.
        :type index: int
        :type val: int
        :rtype: void
        """

        if index == 0:
            self.addAtHead(val)
            return

        cur = self.head
        prev = None
        while index and cur:
            prev = cur
            cur = cur.next
            index -= 1
        if prev:
            if cur:
                new = Node(val)
                new.next = cur
                prev.next = new
            else:
                prev.next = Node(val)

    def deleteAtIndex(self, index):
        """
        Delete the index-th node in the linked list, if the index is valid.
        :type index: int
        :rtype: void
        """

        cur = self.head
        prev = None
        while index and cur:
            prev = cur
            cur = cur.next
            index -= 1
        if prev and cur:
            prev.next = cur.next

    def __repr__(self):
        s = ''
        cur = self.head
        while cur:
            s += str(cur.val) + ' -> '
            cur = cur.next
        return 'linked_list:' + str(s if self.head else 'None')


import time

# funcs = ["addAtHead","deleteAtIndex","addAtHead","addAtHead","addAtHead","addAtIndex","addAtHead","addAtHead","deleteAtIndex","deleteAtIndex","addAtHead","addAtTail","addAtHead","addAtIndex","addAtIndex","addAtHead","get","addAtHead","addAtIndex","addAtIndex","addAtHead","addAtTail","get","addAtHead","deleteAtIndex","get","get","addAtIndex","addAtTail","get","get","addAtTail","addAtHead","addAtTail","addAtTail","addAtHead","get","addAtIndex","get","addAtHead","addAtHead","addAtTail","addAtHead","get","addAtTail","addAtHead","addAtHead","get","addAtHead","addAtHead","addAtHead","addAtIndex","get","addAtTail","addAtHead","addAtHead","addAtTail","get","addAtIndex","deleteAtIndex","get","addAtTail","addAtTail","get","addAtIndex","addAtIndex","addAtTail","addAtHead","addAtHead","addAtTail","addAtTail","addAtTail","addAtHead","addAtIndex","addAtTail","addAtHead","addAtTail","addAtTail","addAtTail","deleteAtIndex","deleteAtIndex","addAtTail","addAtHead","addAtTail","addAtTail","get","addAtIndex","addAtTail","addAtHead","addAtTail","addAtIndex","addAtHead","addAtTail","addAtIndex","addAtIndex","addAtIndex","addAtTail","addAtTail","addAtHead","deleteAtIndex","addAtIndex"]
# params = [[24],[1],[79],[10],[51],[3,37],[92],[53],[6],[5],[6],[33],[47],[7,42],[6,40],[82],[9],[37],[6,84],[2,50],[21],[22],[6],[51],[7],[10],[2],[3,5],[8],[15],[6],[89],[32],[99],[65],[51],[9],[15,62],[20],[83],[10],[3],[10],[3],[21],[22],[22],[7],[87],[73],[85],[19,17],[29],[2],[23],[88],[21],[6],[20,46],[4],[38],[59],[36],[36],[32,99],[23,79],[84],[82],[89],[98],[48],[75],[55],[4,24],[90],[8],[24],[7],[17],[37],[10],[32],[15],[9],[18],[19],[53,96],[31],[11],[96],[4,44],[69],[65],[33,22],[38,55],[31,31],[12],[0],[47],[65],[54,37]]

funcs = ["addAtHead", "addAtTail", "addAtIndex", "get", "deleteAtIndex", "get"]
params = [[1], [3], [1, 2], [1], [1], [1]]

obj = MyLinkedList()
for idx, item in enumerate(funcs):
    command = 'obj.{}(*'.format(item) + str(params[idx]) + ')'
    print(command)
    exec(command)
    print(obj)
    time.sleep(1)