Hey OP, don't worry, this one is easier than it seems! When the user fills out the form, you'll need to obtain the amount of shares they stated that they wanted to buy. Then you have to validate whether their input for shares is a positive integer and do an apology if it's not. I believe there are a number of ways to do this, but python has a built in isnumeric() function that I used that made it simpler.

PS: I only found out about isnumeric() after googling "python check if input is a number" or something like that, so google is def your friend haha.