a__from X cons mark X from s X a__first 0 Z nil a__first s X cons Y Z cons mark Y first X Z a__sel 0 cons X Z mark X a__sel s X cons Y Z a__sel mark X mark Z mark from X a__from mark X mark first X1 X2 a__first mark X1 mark X2 mark sel X1 X2 a__sel mark X1 mark X2 mark cons X1 X2 cons mark X1 X2 mark s X s mark X mark 0 0 mark nil nil a__from X from X a__first X1 X2 first X1 X2 a__sel X1 X2 sel X1 X2 a__from 1 cons 2 mark 1 from 1 s 1 a__first 2 0 0 nil 0 first 2 a__sel 2 sel 2 INNERMOST ./TRS/TRCSR/inn/Ex1_Luc02b_GM.trs