problem defining function(python)

[Python player 0]

hello there

Im making a small thing that make the price of your car...

but there is no thing happened the python say there is no error

but I need a result  there is no resulet i def days by what you are writing (I know its simple cause i didnt add any if for check this cause i test my self...)

but the days cant transfer to cost why that happend ?

this is my code

	print "hello there"
print "but the days that you want to but your car there"
days = raw_input()
def rental_car_cost():
    cost = str(days) * 40
    if days >= 7:
        return cost - 50
    elif days >= 3:
        return cost - 20