1. 문제
https://www.acmicpc.net/problem/9498
2. 풀이
2.1. 내풀이
N = int(input())
if N >= 90 :
print('A')
elif N >= 80:
print('B')
elif N >= 70:
print('C')
elif N >= 60:
print('D')
else:
print('F')
2.2. 숏코딩
print('FFFFFFDCBAA'[int(input())//10])