YES

Problem:
 a__from(X) -> cons(mark(X),from(s(X)))
 a__length(nil()) -> 0()
 a__length(cons(X,Y)) -> s(a__length1(Y))
 a__length1(X) -> a__length(X)
 mark(from(X)) -> a__from(mark(X))
 mark(length(X)) -> a__length(X)
 mark(length1(X)) -> a__length1(X)
 mark(cons(X1,X2)) -> cons(mark(X1),X2)
 mark(s(X)) -> s(mark(X))
 mark(nil()) -> nil()
 mark(0()) -> 0()
 a__from(X) -> from(X)
 a__length(X) -> length(X)
 a__length1(X) -> length1(X)

Proof:
 WPO Processor:
  algebra: Max
  weight function:
   w0 = 0
   w(length1) = w(length) = w(a__length1) = w(0) = w(a__length) = w(nil) = w(
   cons) = w(from) = w(s) = w(mark) = w(a__from) = 0
  status function:
   st(cons) = [1, 0]
   st(length1) = st(length) = st(a__length1) = [0]
   st(0) = []
   st(a__length) = [0]
   st(nil) = []
   st(from) = st(s) = st(mark) = st(a__from) = [0]
  subterm penalty function:
   sp(cons, 0) = sp(from, 0) = sp(a__from, 0) = 1
   sp(length1, 0) = sp(length, 0) = sp(a__length1, 0) = sp(a__length, 0) = sp(
   cons, 1) = sp(s, 0) = sp(mark, 0) = 0
  precedence:
   mark > a__from > cons > a__length1 > a__length > length1 ~ length ~ 0 ~ nil ~ from ~ s
  problem:
   
  Qed