Program I (What Time Is It?)

Write a program to time an event. Prompt the user to enter the starting hour. Prompt the user again to enter the number of hours that have elapsed. Write out what the time will be. 

  Enter starting hour: 11
  Enter duration of event in hours: 53

  At the end of the event the hour hand will show: 4
Here is the skeleton of the code to get you started. I want you to fill in the rest: 
  def main():
    hr = input ("Enter starting hour: ")
    evt = input ("Enter duration of event in hours: ")

    time = ...
What changes would you make to the time assignment if the evt took place in the past and hr was the ending hour?