declare
fun {Countsingle L1#Lsub}
　 if Lsub == nil then true
　 elseif L1 == nil then false
　 elseif L1.1 == Lsub.1 then {Countsingle L1.2#Lsub.2}
　 else false
　 end
end

declare
fun {Countsub L1#Lsub}
　 if L1 == nil then 0
　 elseif {Countsingle L1#sub} then {Countsub L1#Lsub.2} + 1
　 else {Countsub L1#Lsub.2}
　 end
end