You are getting the input prompt twice since you are using 'input' keyword twice.
The solution for that is, by getting input from user first and then printing cube:
num = int(input("Please enter a Number: "))
print("The cube of ", num, "is ", pow(num, 3))
This might come in handy for simple cases. But there are a lot more ways to get the desired output which helps a lot in complex cases.
Using % Formatting
print("The cube of %d is %d" %(num, pow(num, 3)))
Using str.format
print("The cube of {} is {}".format(num, pow(num,3)))
Using f-strings
print(f"The cube of {num} is {pow(num,3)}")
All the above methods will give you the same result.
You can read more about them in a simpler way here.
If you really want to do this in a single line of code, you can use a lambda function with f-strings to achieve it like this:
print((lambda num: f"The cube of {num} is {pow(num,3)}")(int(input("Please enter a Number: "))))
All the best in learning and mastering Python.