Write a program that takes an image in any mode, and performs a $180$ degree rotation of the image to produce an output image.

The program should ask the user to enter a filename, open this file, perform the transformation and then save the rotated version of the image to the file 'output.png$\text{'}.$

Here is an example of the effect your program should produce:

Astronaut

astronaut.png

Enter a filename: astronaut.png

Upside$-$down astronaut