How many movies have Leonid Gaidai and Sergei Filippov collaborated on?

They have worked on 9 movies together! Their first movie together was Sovershenno seryozno (1961) while their highest rated movie together was Ivan Vasilyevich Changes His Profession (1973). They have not worked together since Private Detective, or Operation Cooperation (1989). They are most known for their comedy films together.