MAYBE

We are left with following problem, upon which TcT provides the
certificate MAYBE.

Strict Trs:
  { lessElements(l, t) -> lessE(l, t, 0())
  , lessE(l, t, n) ->
    if(le(length(l), n), le(length(toList(t)), n), l, t, n)
  , if(true(), b, l, t, n) -> l
  , if(false(), true(), l, t, n) -> t
  , if(false(), false(), l, t, n) -> lessE(l, t, s(n))
  , le(0(), m) -> true()
  , le(s(n), 0()) -> false()
  , le(s(n), s(m)) -> le(n, m)
  , length(nil()) -> 0()
  , length(cons(n, l)) -> s(length(l))
  , toList(leaf()) -> nil()
  , toList(node(t1, n, t2)) ->
    append(toList(t1), cons(n, toList(t2)))
  , append(nil(), l2) -> l2
  , append(cons(n, l1), l2) -> cons(n, append(l1, l2))
  , a() -> c()
  , a() -> d() }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..