A production company needs to transport their equipment and staff for a movie they are shooting using large mobile production units or small mobile production units. Large mobile production units can hold 6 people and takes up 2 parking spots whereas small mobile production units can hold only 2 people and takes up 1 parking spot. Movie stars prefer to have their small mobile production unit to share with a close staff, therefore at least 5 units must be small mobile units. However, due to logistic limitations, large mobile production units are more space efficient per spot, they must make up at least 75% of all vehicles. If the movie needs to transport 80 people, minimize the total number of parking spots required by this production.