from turtle import *

def tree(n):
    tree2(n, 0, 0, 2**n)

# bez kresleni vrcholu
def tree2(n, x, y, width):
    # trivialni pripady
    if(n == 0 or n == 1):
        return
    # strom nejmensi hloubky (hloubky 2) s rameny
    if(n == 2):
        pu()
        goto(x, y)
        pd()
        goto(x+width/4, y-20)
        pu()
        goto(x, y)
        pd()
        goto(x-width/4, y-20)
        pu()
    # vetsi stromy vyresime rekurzi
    else:
        tree2(2, x, y, width)
        tree2(n-1, x-width/4, y-20, width/2)
        tree2(n-1, x+width/4, y-20, width/2)


# vcetne kresleni vrcholu
def tree3(n, x, y, width):
    if(n == 0):
        return
    if(n == 1):
        pd()
        circle(3)
        pu()
        return
    if(n == 2):
        pu()
        goto(x, y)
        pd()
        circle(3)
        goto(x+width/4, y-20)
        circle(3)
        pu()
        goto(x, y)
        pd()
        goto(x-width/4, y-20)
        circle(3)
        pu()
    else:
        tree3(2, x, y, width)
        tree3(n-1, x-width/4, y-20, width/2)
        tree3(n-1, x+width/4, y-20, width/2)