Nice thread, thanks for bumping it up. Now I've remembered that gotta figure out such counter for an association lists.
(list
'("A" "B" 10)
'("A" "C" 20)
'("B" "C" 10)
'("A" "B" 10)
'("A" "C" 20)
'("A" "B" 10)
)
-->
(list
'(("A" "B" 10) . 3)
'(("A" "C" 20) . 2)
'(("B" "C" 10) . 1)
)