How many movies have Eiji Wakamatsu and Hiroaki Hirata collaborated on?

They have worked on 7 movies together! Their first movie together was Fullmetal Alchemist the Movie: The Sacred Star of Milos (2011) while their highest rated movie together was Is It Wrong to Try to Pick Up Girls in a Dungeon?: Arrow of the Orion (2019). They have not worked together since Mobile Suit Gundam Hathaway (2021). They are most known for their animation films together.