多分支结构练习，货物的问题，求解

# 用户输入需要计算的工资金额，并赋值给变量salary
salary = input('请输入工资金额：')

# 将工资金额格式化为数字类型
salary_val = eval(salary)

# 给税率赋值
cess1 = 0.03
cess2 = 0.04

# 给应缴税额赋值0
amount = 0

# 算法实现并打印
if(salary_val < 5000):
    print("{:.2f}".format(amount))
elif(5000 <= salary_val <= 20000):
    amount  = salary_val * cess1
    print("{:.2f}".format(amount))
else
    amount  = salary_val * cess2
    print("{:.2f}".format(amount))