Description
When score≥90, the grade is A; when 80≤score<90, the grade is B; when 70≤score<80, the grade is C; when 60≤score<70, the grade is D; when score<60 when the grade is E.This problem requires printing the grade corresponding to the score.
Input
Given a positive integer n from 0 to 100
Output
The grade corresponding to the score