class Node:
    def __init__(self, data):
        self.left = None
        self.right = None
        self.data = data

def fillTree():
    root = Node(11)
    root.left = Node(6)
    root.right = Node(19)
    root.left.left = Node(4)
    root.left.right = Node(8)
    root.right.left = Node(17)
    root.right.right = Node(43)
    root.left.left.right = Node(5)
    root.left.right.right = Node(10)
    root.right.right.left = Node(31)
    root.right.right.right = Node(49)
    return root

def inorder(node):
    print("to be implement")

def preorder(node):
    print("to be implement")

def postorder(node):
    print("to be implement")


root = fillTree()

print("inorder:")
inorder(root);

print("preorder:")
preorder(root)

print("postorder:")
postorder(root)