How many movies have Josef Müller and Oldřich Velen collaborated on?

They have worked on 9 movies together! Their first movie together was Vysoká modrá zeď (1974) while their highest rated movie together was Pan Vok odchází (1980). They have not worked together since Příště budeme chytřejší, staroušku! (1982). They are most known for their comedy films together.