YES

TRS:

  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)

linear polynomial interpretations on N:

  active_A(x1) = x1
  active#_A(x1) = x1 + 2
  fst_A(x1,x2) = x1 + x2 + 14
  fst#_A(x1,x2) = 15
  0_A = 1
  0#_A = 12
  mark_A(x1) = x1
  mark#_A(x1) = x1 + 9
  nil_A = 4
  nil#_A = 0
  s_A(x1) = 3
  s#_A(x1) = 0
  cons_A(x1,x2) = x1 + 7
  cons#_A(x1,x2) = 14
  from_A(x1) = x1 + 15
  from#_A(x1) = x1 + 1
  add_A(x1,x2) = x1 + x2 + 12
  add#_A(x1,x2) = 13
  len_A(x1) = x1 + 5
  len#_A(x1) = 13

precedence:

  cons > len > 0 > active > add > mark > fst = from > nil = s