Write a Python program that will ask a student how many points they have at the end of the semester and then what the total number of points were available for that semester. Then the program will print out their letter grade where an 'A' means that they scored 90% or better in the course, a 'B' is 80% or better, a 'C' is 70% or better, a 'D' is 60% or better, and a 'D' is less than 60%.