####################
# Name :
# UTA ID :
# Lab assignment #3
# Program purpose :
#     Read in two positive integers named start and end from the user
#     and calculate the sum of all the numbers from start to end.  Print 
#     a message giving start, end, and the sum.  If the inputs are not valid,
#     print a message for the user to tell them this.
# Required components :
#     input, print, while loop, if for input validation
# Restrictions :
#     may not use built-in range function for this program
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### main ###