# 输入分数
score = float(input("请输入分数（0-100）: "))
# 判断分数是否在有效范围内
if score < 0 or score > 100:
    print("输入的成绩不正确")
else:
    # 根据分数判断等级
    if score >= 90:
        grade = "优"
    elif score >= 80:
        grade = "良"
    elif score >= 70:
        grade = "中"
    elif score >= 60:
        grade = "及格"
    else:
        grade = "不及格"

    # 输出结果
    print(f"分数: {score}分")
    print(f"等级: {grade}")