How to determine which categories will be used in post url?

I have ordinary posts an categories. Category parent structure is:

City (category)

  New York

  Paris

  Milano

Designer (category)

  Vera Wang

  Alexander McQueen

For every post I check City and Designer but I want my post to have following url structure:
/city/new-york/my-post

WordPress is automatically inserting city and designer.

Is there any way that I can say to wp post to have url structure as I just mentioned.

Thank you