Help me wth python programming?

Hi , i am beginner of python programming. I downloaded python in my computer but when i write
def main():
celsius= eval (input("what is the celsius temperature ?"))
fahrenheit= 9/5 * celsius +32
print ("the temperature is ", fahrenheit, "degrees Fahrenheit.")
main()



i am supposed to get the converted answer. but when i run the module i am getting only
>>>what is the celsius temperature?
nothing else can u guys give me any solution i know i typed perfectly from book do i need to do anything after installing python to work it correctely