score = int (input ('请输入一个分数:'))
if 100 >= score >= 90:
print ('A')
elif 90 > score >= 80:
print ('B')
elif 80 > score >= 60:
print ('C')
elif 60 > score >= 0:
print ('D')
else:
print ('输入错误!')
score = int (input ('请输入一个分数:'))
if 100 >= score >= 90:
print ('A')
elif 90 > score >= 80:
print ('B')
elif 80 > score >= 60:
print ('C')
elif 60 > score >= 0:
print ('D')
else:
print ('输入错误!')