YES

TRS:

  fst(0(),Z) -> nil()
  fst(s(),cons(Y)) -> cons(Y)
  from(X) -> cons(X)
  add(0(),X) -> X
  add(s(),Y) -> s()
  len(nil()) -> 0()
  len(cons(X)) -> s()

max/plus interpretations on N:

  fst_A(x1,x2) = max{0, x1, x2}
  fst#_A(x1,x2) = max{0, x1, x2}
  0_A = 0
  0#_A = 0
  nil_A = 0
  nil#_A = 0
  s_A = 0
  s#_A = 0
  cons_A(x1) = max{0, x1}
  cons#_A(x1) = max{0, x1}
  from_A(x1) = max{0, x1}
  from#_A(x1) = max{0, x1}
  add_A(x1,x2) = max{0, x1, x2}
  add#_A(x1,x2) = max{0, x1, x2}
  len_A(x1) = max{0, x1}
  len#_A(x1) = max{0, x1}

precedence:

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