How many movies have Bibhutibhushan Bandyopadhyay and Shakti Bandyopadhyay collaborated on?

They have worked on 4 movies together! Their first movie together was Nimantran (1971) while their highest rated movie together was Sriman Prithviraj (1973). They have not worked together since Alo (2003). They are most known for their drama films together.