module StringSet = Set.Make(
    struct
        type t = String
        let compare = Pervasives.compare
    end
)

module StringSetUtils =
    struct

        let leidub_aga (s_set) =
            if not (StringSet.is_empty(s_set)) then (
                let set = ref(s_set) in
                let el = ref(StringSet.min_elt(s_set)) in
                set := StringSet.remove !el !set;

                while not (StringSet.is_empty(!set)) && !el == "" do
                    el := StringSet.min_elt(!set);
                    set := StringSet.remove(!el, !set);
                done;

                if !el != "" then (
                    String.get(!el, 0) == 'a'
                ) else
                    false
            );
            false

    end