I have a problem on a sample exam paper I'm stuck with:

The cars in a city are numbered 1 to N. You are allowed to observe 1 car's number. What is the maximum likelihood estimate of N based on this single observation.

I'm also given the hint that the parameter is a positive integer so L becomes a list of probabilities, one associated with each N.

I don't have a great understanding of this module as my lecturer has been terrible, so any help is appreciated.