This is my code and I can't figure out whats wrong with it

# hotel cost

def hotel_cost(nights):

return hotel_cost(140 * nights)

# plane ticket cost

def plane_ride_cost(city):

if city == "Charlotte":

return 183

elif city == "Tampa":

return 220

elif city == "Pittsburgh":

return 222

elif city == "Los Angeles":

return 475

# rental car rent

def rental_car_cost(days):

rent = 40 * days

if days >= 7:

rent -= 50

elif days >= 3:

rent -= 20

return rent

# total cost

def trip_cost(city, days):

return hotel_cost(nights) + plane_ride_cost(city) + rental_car_cost(days)

getting this error

Oops, try again. hotel_cost(1) raised an error: maximum recursion depth exceeded

Any help woul be greatly appreciated