Pytorch: Editing and re-organising directories

I am working with a dataset in the format: It is a series of images and their respective object segmentation masks from 15 long videos. I want to re-organise it from:
Folder/
class1/
x/
image1.png
image2.png

y/
mask_image1.png
mask_image2.png

class2/
x/
image50.png
y/
mask_image50.png

to:
Folder/
x/
class1/
image1.png

class2/
image50.png

y/
class1/
mask_image1.png

class2/
mask_image50.png

Any help would be great!