কলম নিবা?

Score: 5 Points

Rafin, Rahul, Zahid and Jubaer are in a group of 13 members. In how many total ways 6 red, 3 green and 4 blue pens can be distributed among them so that everyone gets 1 pen and Rafin and Zahid get the same colored pen but Rahul and Jubaer don't get the same colored pen?