active fst 0 Z mark nil active fst s X cons Y Z mark cons Y fst X Z active from X mark cons X from s X active add 0 X mark X active add s X Y mark s add X Y active len nil mark 0 active len cons X Z mark s len Z mark fst X1 X2 active fst mark X1 mark X2 mark 0 active 0 mark nil active nil mark s X active s X mark cons X1 X2 active cons mark X1 X2 mark from X active from mark X mark add X1 X2 active add mark X1 mark X2 mark len X active len mark X fst mark X1 X2 fst X1 X2 fst X1 mark X2 fst X1 X2 fst active X1 X2 fst X1 X2 fst X1 active X2 fst X1 X2 s mark X s X s active X s X cons mark X1 X2 cons X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 cons X1 active X2 cons X1 X2 from mark X from X from active X from X add mark X1 X2 add X1 X2 add X1 mark X2 add X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 len mark X len X len active X len X 2.2 active fst s X cons Y Z cons Y fst X Z active from X from s X active add s X Y mark s add X Y fst X1 mark X2 fst X1 X2 mark fst X1 X2 active fst mark X1 mark X2 active from X cons X from s X active from X mark cons X from s X fst X1 active X2 fst X1 X2 mark fst X1 X2 fst mark X1 mark X2 active add 0 X mark X mark fst X1 X2 mark X1 from mark X from X mark from X active from mark X fst mark X1 X2 fst X1 X2 mark len X len mark X mark cons X1 X2 active cons mark X1 X2 mark 0 active 0 cons active X1 X2 cons X1 X2 active len cons X Z mark s len Z s mark X s X active fst 0 Z mark nil cons X1 mark X2 cons X1 X2 active add s X Y add X Y mark cons X1 X2 cons mark X1 X2 active add s X Y s add X Y mark len X mark X mark fst X1 X2 mark X2 active len cons X Z s len Z mark add X1 X2 mark X2 mark from X from mark X s active X s X mark s X active s X cons mark X1 X2 cons X1 X2 active len nil mark 0 active from X s X len active X len X cons X1 active X2 cons X1 X2 from active X from X mark nil active nil mark add X1 X2 active add mark X1 mark X2 add mark X1 X2 add X1 X2 mark add X1 X2 mark X1 active len cons X Z len Z len mark X len X add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 active fst s X cons Y Z fst X Z active fst s X cons Y Z mark cons Y fst X Z fst active X1 X2 fst X1 X2 mark from X mark X mark cons X1 X2 mark X1 add X1 mark X2 add X1 X2 mark len X active len mark X mark add X1 X2 add mark X1 mark X2 true mark len X active len mark X mark len X mark X mark fst X1 X2 mark X2 mark cons X1 X2 mark X1 mark from X mark X active fst s X cons Y Z mark cons Y fst X Z active len cons X Z mark s len Z mark cons X1 X2 active cons mark X1 X2 mark add X1 X2 mark X1 mark add X1 X2 active add mark X1 mark X2 mark from X active from mark X mark fst X1 X2 mark X1 active add 0 X mark X active from X mark cons X from s X mark s X active s X mark fst X1 X2 active fst mark X1 mark X2 active add s X Y mark s add X Y mark add X1 X2 mark X2 true len 1 0 cons 2 0 s 1 8386 fst 2 1 2 6296 fst 2 0 mark 1 1 14681 0 0 297 from 1 1 37749 s 1 0 nil 0 402 mark 1 1 0 from 1 0 active 1 1 0 cons 2 1 23067 active 1 1 0 add 2 0 add 2 1 2 14682 len 1 1 1 fst active X1 X2 fst X1 X2 active add 0 X mark X mark len X active len mark X mark fst X1 X2 active fst mark X1 mark X2 active fst 0 Z mark nil active from X mark cons X from s X fst mark X1 X2 fst X1 X2 s active X s X from mark X from X fst X1 active X2 fst X1 X2 len mark X len X fst X1 mark X2 fst X1 X2 from active X from X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 active add s X Y mark s add X Y len active X len X mark nil active nil active len cons X Z mark s len Z s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 mark add X1 X2 active add mark X1 mark X2 add X1 active X2 add X1 X2 mark cons X1 X2 active cons mark X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 mark s X active s X mark 0 active 0 mark from X active from mark X active len nil mark 0 add X1 mark X2 add X1 X2 active fst s X cons Y Z mark cons Y fst X Z mark from X from mark X false active fst s X cons Y Z cons Y fst X Z false active fst s X cons Y Z fst X Z false active len nil mark 0 false mark 0 active 0 false active len cons X Z s len Z false active len cons X Z len Z false mark cons X1 X2 cons mark X1 X2 false active add s X Y s add X Y false active add s X Y add X Y false mark add X1 X2 add mark X1 mark X2 false add X1 mark X2 add X1 X2 add X1 active X2 add X1 X2 add active X1 X2 add X1 X2 add mark X1 X2 add X1 X2 true len 1 0 cons 2 0 s 1 57757 fst 2 1 fst 2 0 mark 1 1 14681 0 0 297 from 1 1 2 s 1 0 nil 0 7746 mark 1 1 3 from 1 0 active 1 1 1 cons 2 1 1 active 1 0 add 2 2 0 add 2 1 len 1 1 add mark X1 X2 add X1 X2 add active X1 X2 add X1 X2 s active X s X len mark X len X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 len active X len X s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 add X1 mark X2 add X1 X2 add mark X1 X2 add X1 X2 add active X1 X2 add X1 X2 true len 1 0 cons 2 0 s 1 57757 fst 2 7177 fst 2 0 mark 1 1 14681 0 0 297 from 1 1 1 s 1 0 nil 0 15837 mark 1 1 3 from 1 0 active 1 1 1 cons 2 1 43653 active 1 0 add 2 1 0 add 2 1 len 1 112 s active X s X len mark X len X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 len active X len X s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 add X1 mark X2 add X1 X2 active from X cons X from s X false cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 cons X1 active X2 cons X1 X2 cons mark X1 X2 cons X1 X2 true len 1 0 cons 2 1 2 0 s 1 27857 fst 2 2 fst 2 0 mark 1 1 14681 0 0 297 from 1 1 2 s 1 0 nil 0 15837 mark 1 1 3 from 1 0 active 1 1 1 cons 2 1 1 active 1 0 add 2 0 add 2 1 len 1 1 s active X s X len mark X len X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 len active X len X s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 add X1 mark X2 add X1 X2 active from X from s X false from mark X from X from active X from X true len 1 0 cons 2 0 s 1 1 fst 2 2 fst 2 0 mark 1 1 14681 0 0 42085 from 1 1 2743 s 1 0 nil 0 44079 mark 1 1 3 from 1 1 0 active 1 1 1 cons 2 1 31934 active 1 0 add 2 0 add 2 1 len 1 2 s active X s X len mark X len X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 len active X len X s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 add X1 mark X2 add X1 X2 active from X s X false s mark X s X s active X s X true len 1 0 cons 2 0 s 1 1 fst 2 3047 fst 2 0 mark 1 1 14681 0 0 42085 from 1 1 1 s 1 1 0 nil 0 24198 mark 1 1 19046 from 1 0 active 1 1 1 cons 2 1 54921 active 1 0 add 2 0 add 2 19044 len 1 11575 s active X s X len mark X len X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 len active X len X s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 add X1 mark X2 add X1 X2 active fst 0 Z mark nil false mark nil active nil false mark fst X1 X2 fst mark X1 mark X2 false fst active X1 X2 fst X1 X2 fst mark X1 X2 fst X1 X2 fst X1 active X2 fst X1 X2 fst X1 mark X2 fst X1 X2 true len 1 0 cons 2 0 s 1 22775 fst 2 12701 fst 2 1 2 0 mark 1 1 14681 0 0 19642 from 1 1 14923 s 1 0 nil 0 24198 mark 1 1 46871 from 1 0 active 1 1 1 cons 2 1 36560 active 1 0 add 2 0 add 2 46869 len 1 25728 s active X s X len mark X len X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 len active X len X s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 add X1 mark X2 add X1 X2 mark len X len mark X false len mark X len X len active X len X true len 1 1 0 cons 2 0 s 1 29273 fst 2 436 fst 2 0 mark 1 1 14681 0 0 58185 from 1 1 14459 s 1 0 nil 0 41866 mark 1 1 32573 from 1 0 active 1 1 1 cons 2 1 32499 active 1 0 add 2 0 add 2 32571 len 1 32582 s active X s X len mark X len X cons mark X1 X2 cons X1 X2 add mark X1 X2 add X1 X2 len active X len X s mark X s X cons X1 active X2 cons X1 X2 add active X1 X2 add X1 X2 add X1 active X2 add X1 X2 cons X1 mark X2 cons X1 X2 cons active X1 X2 cons X1 X2 add X1 mark X2 add X1 X2 NaTT certifiable-1.6