YES

TRS:

  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)

max/plus interpretations on N:

  a__fst_A(x1,x2) = max{26, x1, 15 + x2}
  a__fst#_A(x1,x2) = max{29, -6 + x1, 24 + x2}
  0_A = 0
  0#_A = 27
  nil_A = 16
  nil#_A = 28
  s_A(x1) = max{8, 28}
  s#_A(x1) = max{0, 1}
  cons_A(x1,x2) = max{41, 6 + x1, 1}
  cons#_A(x1,x2) = max{24, 30, 2}
  mark_A(x1) = max{7, 10 + x1}
  mark#_A(x1) = max{26, 30 + x1}
  fst_A(x1,x2) = max{16, x1, 15 + x2}
  fst#_A(x1,x2) = max{0, 3, 23}
  a__from_A(x1) = max{10, 41 + x1}
  a__from#_A(x1) = max{29, 60 + x1}
  from_A(x1) = max{0, 41 + x1}
  from#_A(x1) = max{28, 31 + x1}
  a__add_A(x1,x2) = max{28, 29 + x1, 12 + x2}
  a__add#_A(x1,x2) = max{43, 15 + x1, 31 + x2}
  add_A(x1,x2) = max{17, 29 + x1, 12 + x2}
  add#_A(x1,x2) = max{14, 42, 14}
  a__len_A(x1) = max{7, x1}
  a__len#_A(x1) = max{25, 25}
  len_A(x1) = max{0, x1}
  len#_A(x1) = max{1, 1}

precedence:

  a__fst > fst = from = add > mark > nil = a__add > 0 > cons = a__len > s = len > a__from