python

3. Write a program that lets the user enter a nonnegative integer then uses a loop to calculate the cumulative sum associated with that number. Display the cumulative sum. For example, The cumulative sum associated with 5 is 15 because (1 + 2 + 3+ 4+ 5) = 15 The cumulative sum associated with 3 is 6 because (1 + 2 + 3) = 6