grade=io.read("*n")
if (grade>=90)
then
    print("You have scored an O")
elseif (grade<90)and(grade>=80)
then
    print("You have scored an A")
elseif (grade<80)and(grade>=70)
then
    print("You have scored a B")
else (grade<70)
    print ("You have scored a C")
end