Easy~~ python解法

n = input()
if n == 'A' or n == 'a' :
print("90~100")
if n == 'B' or n == 'b' :
print("80~89")
if n == 'C' or n == 'c' :
print("70~79")
if n == 'D' or n == 'd' :
print("60~69")
if n == 'E' or n == 'e' :
print("0~59")