Left side
Got to File/automate/photomerge.
This is what you get:
Click on perspective box (in settings), the image
adjusts itself to parallel the perspective.
to do. Go to free transform:perspective and bring
the right corner down till the perspective is visually correct.
Click the move tool to apply transformation.
Great photo! for fun, you can use the paint bucket tool
with the color of your choice and fill in the blank space.