a__fst 0 Z nil a__fst s X cons Y Z cons mark Y fst X Z a__from X cons mark X from s X a__add 0 X mark X a__add s X Y s add X Y a__len nil 0 a__len cons X Z s len Z mark fst X1 X2 a__fst mark X1 mark X2 mark from X a__from mark X mark add X1 X2 a__add mark X1 mark X2 mark len X a__len mark X mark 0 0 mark s X s X mark nil nil mark cons X1 X2 cons mark X1 X2 a__fst X1 X2 fst X1 X2 a__from X from X a__add X1 X2 add X1 X2 a__len X len X 2.2 mark from X a__from mark X mark add X1 X2 a__add mark X1 mark X2 mark cons X1 X2 mark X1 a__from X mark X mark fst X1 X2 mark X1 mark fst X1 X2 mark X2 a__add 0 X mark X mark add X1 X2 mark X1 mark fst X1 X2 a__fst mark X1 mark X2 mark len X mark X mark from X mark X a__fst s X cons Y Z mark Y mark add X1 X2 mark X2 mark len X a__len mark X true a__add 0 X mark X mark fst X1 X2 mark X2 mark add X1 X2 mark X2 a__fst s X cons Y Z mark Y mark from X mark X mark fst X1 X2 mark X1 a__from X mark X mark cons X1 X2 mark X1 mark add X1 X2 a__add mark X1 mark X2 mark len X mark X mark fst X1 X2 a__fst mark X1 mark X2 mark add X1 X2 mark X1 mark from X a__from mark X true a__len 1 0 s 1 1 a__from 1 1 1 a__from 1 1 2 a__add 2 2 1 fst 2 1 2 1 a__add 2 1 2 11799 a__fst 2 1 2 1 mark 1 1 0 0 0 7183 from 1 1 2 nil 0 3267 mark 1 1 0 a__len 1 1 8366 cons 2 1 1 add 2 1 2 11799 a__fst 2 2 0 len 1 1 8366 a__add X1 X2 add X1 X2 a__add 0 X mark X mark cons X1 X2 cons mark X1 X2 mark fst X1 X2 a__fst mark X1 mark X2 a__fst 0 Z nil a__from X cons mark X from s X a__fst X1 X2 fst X1 X2 a__len X len X a__from X from X a__add s X Y s add X Y mark add X1 X2 a__add mark X1 mark X2 a__len cons X Z s len Z mark nil nil mark 0 0 mark len X a__len mark X mark from X a__from mark X mark s X s X a__len nil 0 a__fst s X cons Y Z cons mark Y fst X Z mark len X a__len mark X false NaTT certifiable-1.6