mark=int(input("enter your marks:"))
if(mark>=80 and mark<=100):
    print("A+")
elif(mark>=75 and mark<=79):
    print("A")
elif(mark>=70 and mark<=74):
    print("A-")
elif(mark>=65 and mark<=69):
    print("B+")
elif(mark>=60 and mark<=64):
    print("B")
elif(mark>=55 and mark<=59):
    print("B-")
elif(mark>=50 and mark<=54):
    print("C+")
elif(mark>=45 and mark<=49):
    print("C")
elif(mark>=40 and mark<=44):
    print("D")
else:
    print("Faill")


