[Tutor] Issue w/ while loops

[Rafael Knuth]

Hej there,

I want to use a while loop in a program (version used: Python 3.3.0),
and I expect it to loop unless the user enters an integer or a
floating-point number instead of a string.

print("TIME TRACKING")
hours_worked = input("How many hours did you work today? ")
while hours_worked != str() or int():
    hours_worked = input("Can't understand you. Please enter a number!  ")

print("you worked " + str(hours_worked) + " hours today.")

When I run the program, it keeps looping even if the condition is met.
How do I need to modify the program on the 3rd line so that it stops
looping when the user enters a floating-point number or an integer?

Thank you!

Raf