Temperatures

Write functions to convert from Fahrenheit to Celsius and vice-versa.

Your functions should look like:

def fahrenheit_to_celsius(temp):
    ...

def celsius_to_fahrenheit(temp):
    ...

You'll find conversions in the Fahrenheit Wikipedia article.

Example

Here how your function could be used in an interactive Python interpreter:

>>> celsius_to_fahrenheit(100)
212.0