grade = raw_input("Please enter the letter grade. \n")
whole_grades = {"A":4.0, "B":3.0, "C":2.0, "D":1.0, "F":0.0}
signs = {"+":0.3, "-":-0.3}
if len(grade) == 1:
        print(whole_grades[grade])
elif len(grade) == 2:
        a = list(grade)
        numerical_grade = whole_grades[a[0]]
        numerical_grade += signs[a[1]]
        print(numerical_grade)
else:
        print("YOU HAVE FUCKED UP NOW")