active first 0 X mark nil active first s X cons Y Z mark cons Y first X Z active from X mark cons X from s X active first X1 X2 first active X1 X2 active first X1 X2 first X1 active X2 active s X s active X active cons X1 X2 cons active X1 X2 active from X from active X first mark X1 X2 mark first X1 X2 first X1 mark X2 mark first X1 X2 s mark X mark s X cons mark X1 X2 mark cons X1 X2 from mark X mark from X proper first X1 X2 first proper X1 proper X2 proper 0 ok 0 proper nil ok nil proper s X s proper X proper cons X1 X2 cons proper X1 proper X2 proper from X from proper X first ok X1 ok X2 ok first X1 X2 s ok X ok s X cons ok X1 ok X2 ok cons X1 X2 from ok X ok from X top mark X top proper X top ok X top active X active 1 first 2 0 0 mark 1 nil 0 s 1 cons 2 from 1 proper 1 ok 1 top 1 INNERMOST ./TRS/TRCSR/inn/Ex6_Luc98_C.trs