grade_list = ['A+', 'A0', 'A-', 'B+', 'B0', 'B-', 'C+', 'C0', 'C-', 'D+', 'D0', 'D-', 'F']
score_list = [4.3, 4.0, 3.7, 3.3, 3.0, 2.7, 2.3, 2.0, 1.7, 1.3, 1.0, 0.7, 0.0]
matched_dict = dict(zip(grade_list, score_list))
C = input()
print(matched_dict[C])