def get_score():
    """ asks for test score """
    collect = True
    
    while collect:
        test_score = input("Enter test score: ").strip()
        if test_score.isnumeric():
            test_score = int(test_score)
            if test_score >= 0 and test_score <= 100:
                collect = False
            else:
                print("Invalid input. Please enter a number between 0 and 100.")
        else:
            print("Invalid input. Please enter a number.")
    
    return test_score

def main():
    """ runs all functions """
    test_score = int(get_score())
    
    print("These are the GSCE grade boundaries:")
    if test_score >= 90:
        print("Your grade is 9")
    elif test_score >= 80:
        print("Your grade is 8")
    elif test_score >= 70:
        print("Your grade is 7")
    elif test_score >= 60:
        print("Your grade is 6")
    elif test_score >= 50:
        print("Your grade is 5")
    elif test_score >= 40:
        print("Your grade is 4")
    elif test_score >= 30:
        print("Your grade is 3")
    elif test_score >= 20:
        print("Your grade is 2")
    else:
        print("Your grade is 1")
        
main()