(def grades {
    "A+" "4.0"
    "A"  "4.0"
    "A-" "3.7"
    "B+" "3.3"
    "B" "3.0"
    "B-" "2.7"
    "C+" "2.3"
    "C" "2.0"
    "C-" "1.7"
    "D+" "1.3"
    "D" "1.0"
})

(defn main [_ arg] (print (or (grades arg) "Not a grade")))