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

class MyLinkedList:

    def __init__(self):
        self.head = Node(None)
        self.size = 0

    def get(self, index: int) -> int:

        if index < 0 or index >= self.size:
            return -1

        current = self.head
        for i in range(index+1):
            current = current.next

        return current.val

    def addAtHead(self, val: int) -> None:
        new_head = Node(val)
        self.head.next, new_head.next = new_head, self.head.next
        self.size += 1

    def addAtTail(self, val: int) -> None:
        new_node = Node(val)
        current = self.head
        while current.next:
            current = current.next

        current.next = new_node
        self.size += 1

    def addAtIndex(self, index: int, val: int) -> None:

        if index > self.size:
            return

        if index < 0:
            index = 0

        new_node = Node(val)
        current = self.head
        for i in range(index+1):
            prev = current
            current = current.next

        prev.next, new_node.next = new_node, current
        self.size = self.size + 1


    def deleteAtIndex(self, index: int) -> None:
        if index <0 or index >= self.size:
            return

        current = self.head
        for i in range(index+1):
            prev = current
            current = current.next

        prev.next = current.next
        self.size = self.size - 1



# Your MyLinkedList object will be instantiated and called as such:
# obj = MyLinkedList()
# param_1 = obj.get(index)
# obj.addAtHead(val)
# obj.addAtTail(val)
# obj.addAtIndex(index,val)
# obj.deleteAtIndex(index)