How many movies have Gustav Ehmck and Hubertus Hagen collaborated on?

They have worked on 4 movies together! Their first movie together was Liebesschule blutjunger Mädchen (1973) while their highest rated movie together was Mein Onkel Theodor oder Wie man viel Geld im Schlaf verdient (1975). They have not worked together since News from Robber Hotzenplotz (1979).