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


tree = Node(1)
tree.left = Node(2)
tree.right = Node(3)
tree.left.left = Node(4)
tree.left.right = Node(5)
tree.right.left = Node(6)
tree.right.right = Node(7)


print(tree.left.right.val)