#Our Tree structure
class Node:
 	def __init__(self,value):
 		self.left=None
 		self.data=value
 		self.right=None
class Tree:
 	def __init__(self,root):
 		self.root=Node(root)
tree=Tree(3)
tree.root.left=Node(9)
tree.root.right=Node(20)
tree.root.right.left=Node(15)
tree.root.right.right=Node(7)
###########################################################################################
def inorder(root,visited):
	if root:
 		visited=inorder(root.left,visited) 
 		visited.append(root.data)
 		visited=inorder(root.right,visited) 
 	return visited 
def preorder(root,visited):
 	if root:
 		visited.append(root.data)
 		visited=preorder(root.left,visited)
 		visited=preorder(root.right,visited)
 	return visited #return visited stack
def postorder(root,visited):
	if root: #check if node exits
 		visited=postorder(root.left,visited) 
 		visited=postorder(root.right,visited)
 		visited.append(root.data)
 	return visited
print(f'Inorder (L-V-R)',inorder(tree.root,[]))
print(f'Preorder (V-L-R)',preorder(tree.root,[]))
print(f'Postorder (L-R-v)',postorder(tree.root,[]))