How many movies have Ben Luk Man-Wah and Billy Ching Sau-Yat collaborated on?

They have worked on 3 movies together! Their first movie together was The Millionaires' Express (1986) while their highest rated movie together was The Days of Being Dumb (1992). They have not worked together since The Days of Being Dumb (1992). They are most known for their comedy films together.