# >=90 优
# >=80 良
# >=60 中
# 差
nums = int(input("请输入你的成绩:"))
if nums > 100 or nums < 0:
print("数据错误")
elif nums >= 90:
print("优")
elif nums >= 80:
print("良")
elif nums >= 60:
print("中")
else:
print("差")
# num = int(input("请输入一个数字:"))
# if 有且仅能出现1次,最先判断
# elif 任意多次 0~n,前面条件都不满足才判断
# else 1次或0次,最后判断
# if num == 0:
# print("零")
# elif num % 2 == 0:
# print("偶数")
# else:
# print("奇数")
# if num % 2 == 0:
# if num == 0:
# print("零")
# else:
# print("偶数")
# else:
# print("奇数")
# print("程序结束了")
# dict 字典,map,键值对 key:value
# dict1 = {"zhangsan": 18, "lisi": 19,
# "wangwu": 20, "yanxiaoliu": 45}
# # 通过key值可以获取或修改对应value值
# print(dict1["wangwu"])
# dict1["wangwu"] = 60
# print(dict1["wangwu"])
# # key存在则改之,不存在则加之
# dict1["chenxiaoer"] = 30
# print(dict1)
# # pop()
# dict1.pop("chenxiaoer")
# print(dict1)
# 输入:wu yan zu
# 输出:zu yan wu
# str1 = input("输入:")
# list1 = str1.split(" ")
# list1 = list1[::-1]
# str1 = " ".join(list1)
# print("输出:%s" % str1)
# join() 通过指定字符串连接数列所有元素
# str1 = "."
# list1 = ["127", "0", "0", "1"]
# print(str1.join(list1))
# split() 根据指定字符,将源字符串拆分成一个数列
# str1 = "192.168.17.1"
# list1 = str1.split(".")
# print(list1)
# str2 = "zhang sanxiao"
# xing = str2.split(" ")[0]
# print(xing)
# replace() 字符串指定子串进行替换
# 子串无论出现几次,都会完成替换
# str1 = "ni hao zhang san"
# str1 = str1.replace("zhang", "li")
# print(str1)
# str2 = "ni hao zhang hao"
# str2 = str2.replace("zhang hao", "zhang san")
# print(str2)
# swapcase() 将字符串中字符大小写转换
# str1 = "ZHANG san"
# str1 = str1.swapcase()
# print(str1)
# upper() 将字符串中小写字母转换成大写
# str1 = "ZHANG san"
# str1 = str1.upper()
# print(str1)
# lower() 将字符串中大写字母转换成小写
# str1 = "ZHANG san"
# str1 = str1.lower()
# print(str1)
# strip() 去掉字符串首尾指定字符
# 生成新的字符串,不会对源字符串做修改
# str1 = " zhangsan "
# str1 = str1.strip(" ")
# print(str1)
# find() 寻找子串的位置,没有找到返回-1
# str1 = "zhang san ni hao"
# str2 = "sang"
# print(str1.find(str2))
# # 输入r,求圆的面积
# # 运行效果如下:
# # 请输入圆的半径:1
# # 圆面积为:3.14
# r = float(input("请输入圆的半径:"))
# print("圆面积为:%.2f" % (3.14 * r ** 2))