let rec tryFindPathtoAux v t acc =
    match t with
    | [] -> []:Path
    | t::ts -> tryFindPathto v t acc+1::acc @ tryFindPathtoAux v ts acc:: :Path
and tryFindPathto v t =
    match t with
    | N(n,_) when n = v -> []:Path
    | N(_,ts) -> List.findIndex (isEqual v) ts::(tryFindPathtoAux v ts);;