Professor X would like to distribute shirts to his n 2 3 students to celebrate their work so far in the semester. The professor has unlimited supply of red shirts, blue shirts, and green shirts. He would like to distribute the shirts such that each student receives exactly one shirt and at least one of each color is distributed. To do this, he defines a function f that maps each student :1? to the shirt color the}.' will receive. How man},r such functions exist