Letter Grade Converter Function

# letter_grade_converter_function.py
#   This program accepts an exam score as input and prints out
#   the corresponding grade using a function.
# by: Scott Gordon

def main():
    # Write welcome message.
    print("***** Welcome to The Letter Grade Calculator *****")

    # Get input from user and assign it to score variable.

    score = int(input("Enter your exam score: "))

    def letter_grade_converter(score):

        # Use branching control statements to associate the score
        #       with the letter grade.
        letter_grade = ""
        if score < 60:
            letter_grade = "F"
        elif score < 70:
            letter_grade = "D"
        elif score < 80:
            letter_grade = "C"
        elif score < 90:
            letter_grade = "B"
        elif score < 100:
            letter_grade = "A"

        # Print out the corresponding grade.
        return f"Your letter grade is {letter_grade}."

    print(letter_grade_converter(score))


main()