Hello @abhinavbhatia3557794, welcome to the forums!
Can you send a link to the exercise, please? Quite often, the CC terminal isn’t configured to take input from the user, which means that Python will then throw that error (as no input has been given when it should have). I know it isn’t particularly ideal, but one workaround is to just hardcode a value to each variable that would otherwise take input using input()…
As I suspected, CC’s terminal doesn’t allow for user input there (I don’t know why…); to demonstrate the effect they were trying to, run a similar piece of code:
num = "2" #Because the default type that input returns is a string
print(num ** 2)