我做了一个python程序，我不知道为什么它不工作。
我试过这个代码：

import turtle
screen=turtle.Screen()
opened_door="C:\Users\Roby&Gabry\Desktop\Monty Hall Paradox\opened_door.gif"
closed_door="C:\Users\Roby&Gabry\Desktop\Monty Hall Paradox\closed_door.gif"
screen.addshape(opened_door)
screen.addshape(closed_door)
t=turtle.Turtle()
t.shape(closed_door)

但每次我运行程序它都给我这样的错误：

File "c:\Users\Roby&Gabry\Desktop\Monty Hall Paradox\Monty Hall.py", line 3
    opened_door="C:\Users\Roby&Gabry\Desktop\Monty Hall Paradox\opened_door.gif"
                                                                                ^
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape

错误在哪里？