My approach to solve this is some story, sorry plz!
Let, 'a' our boss so he can rule on 2 elements possibly {(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)} (try to make pair only in this direction 1-->2-->3-->4)
now remaining two slaves 'b' and 'c' can have only one of two elements.
so this way total 12 ways possible for ex { [a-1,2 , b-3 , c-4 , a-1,2 , b-4 , c-3],...} 12 possibilities
Now, it's time to make 'b' as a boss and 12 possibilities
Now, it's time to make 'c' as a boss and 12 possibilities
so, total 12+12+12=36
P.S. this may sound weired but story is the medicine to remember something!