active __ __ X Y Z mark __ X __ Y Z active __ X nil mark X active __ nil X mark X active and tt X mark X active isNePal __ I __ P I mark tt active __ X1 X2 __ active X1 X2 active __ X1 X2 __ X1 active X2 active and X1 X2 and active X1 X2 active isNePal X isNePal active X __ mark X1 X2 mark __ X1 X2 __ X1 mark X2 mark __ X1 X2 and mark X1 X2 mark and X1 X2 isNePal mark X mark isNePal X proper __ X1 X2 __ proper X1 proper X2 proper nil ok nil proper and X1 X2 and proper X1 proper X2 proper tt ok tt proper isNePal X isNePal proper X __ ok X1 ok X2 ok __ X1 X2 and ok X1 ok X2 ok and X1 X2 isNePal ok X ok isNePal X top mark X top proper X top ok X top active X active 1 __ 2 mark 1 nil 0 and 2 tt 0 isNePal 1 proper 1 ok 1 top 1 INNERMOST ./TRS/TRCSR/inn/PALINDROME_nosorts_C.trs