The Hierarchy tree is: 
Ticket (Service with cat=101)
    Air Ticket (Service with cat=100)
        Air Travel (Service with cat=1)
            AirFrance (is a Service Implementation)
            Alitalia (is a Service Implementation)
            Lufthansa (is a Service Implementation)
            SwissAir (is a Service Implementation)
            SAS (is a Service Implementation)
            OlympicAirways (is a Service Implementation)
            TWA (is a Service Implementation)
        Low Cost (Service with cat=17)
            Wizz Air (is a Service Implementation)
            Aegean Airlines (is a Service Implementation)
            RyanAir (is a Service Implementation)
            EasyJet (is a Service Implementation)
            Iberia (is a Service Implementation)
            Germanwings (is a Service Implementation)
        Star Alliance (Service with cat=22)
            Emirates (is a Service Implementation)
            Qatar Airways (is a Service Implementation)
            Turkish Airlines (is a Service Implementation)
            United (is a Service Implementation)
            Delta Airlines (is a Service Implementation)
            EgyptAir (is a Service Implementation)
            Thai (is a Service Implementation)
    Road Travel (Service with cat=2)
        LuxuryBuses (is a Service Implementation)
        EuroLines (is a Service Implementation)
        MagicBus (is a Service Implementation)
    Sea Travel (Service with cat=3)
        HighSpeedFerries (is a Service Implementation)
        HighSpeedVessels (is a Service Implementation)
        SeaLines (is a Service Implementation)
        AquaMarine (is a Service Implementation)
    Train Travel (Service with cat=4)
        Eurostar (is a Service Implementation)
        TGV (is a Service Implementation)
        TrenOse (is a Service Implementation)
        InterRail (is a Service Implementation)
        TrenItalia (is a Service Implementation)
Residence (Service with cat=104)
    Hotel (Service with cat=102)
        Luxury (Service with cat=5)
            GrandResort (is a Service Implementation)
            Costa Navarino (is a Service Implementation)
            Hilton (is a Service Implementation)
        1stClass (Service with cat=6)
            Elunda Beach (is a Service Implementation)
            Corfu Palace (is a Service Implementation)
        2ndClass (Service with cat=7)
            Filoxenia (is a Service Implementation)
            President (is a Service Implementation)
        3rdClass (Service with cat=8)
            MitsosYouthHostel (is a Service Implementation)
            TolisYouthHostel (is a Service Implementation)
    Appartments (Service with cat=9)
        Dora's App (is a Service Implementation)
        Villa Thea (is a Service Implementation)
        Villa Maria (is a Service Implementation)
    Camping (Service with cat=103)
        Free Camping (Service with cat=10)
            Hiliadou Camp (is a Service Implementation)
            Romanos Beach (is a Service Implementation)
            Kaiafas Camp (is a Service Implementation)
        Organized Camping (Service with cat=11)
            Simos Beach (is a Service Implementation)
            Antiparos Beach (is a Service Implementation)
Event (Service with cat=106)
    Athletic (Service with cat=12)
        SportsTicketBooker (is a Service Implementation)
        Football (Service with cat=13)
            EuropeanCup (is a Service Implementation)
            ChampionsLeague (is a Service Implementation)
            WorldCup (is a Service Implementation)
        Basketball (Service with cat=14)
            EuroleagueFinals (is a Service Implementation)
            NBAFinals (is a Service Implementation)
    Culture (Service with cat=105)
        Music (Service with cat=15)
            GrandConsert (is a Service Implementation)
            MagicOpera (is a Service Implementation)
        Painting (Service with cat=16)
            NationalPaintingMuseum (is a Service Implementation)
Seminar (Service with cat=107)
    Informatics (Service with cat=20)
        Python course (is a Service Implementation)
        Data Bases (is a Service Implementation)
        Operating Systems (is a Service Implementation)
        iOS Programming (Service with cat=18)
            ObjectiveC (is a Service Implementation)
            Swift programming (is a Service Implementation)
        Android Programming (Service with cat=19)
            Java for Android (is a Service Implementation)
            Android Apps (is a Service Implementation)
    Telecommunications (Service with cat=21)
        4G course (is a Service Implementation)
        MGW Operation (is a Service Implementation)
        MSC Charging Operation (is a Service Implementation)
        Cisco CCNA (is a Service Implementation)
Activities (Service with cat=108)
    Indoor (Service with cat=23)
        Ping Pong (is a Service Implementation)
    Outdoor (Service with cat=24)
        Golf (is a Service Implementation)
        Ski (is a Service Implementation)
        Tennis (is a Service Implementation)
Hobbies (Service with cat=109)
    Leisure Time (Service with cat=25)
        Cards (is a Service Implementation)
        Spa (is a Service Implementation)
        Tavli (is a Service Implementation)
        Sunbathing (is a Service Implementation)
        Sauna (is a Service Implementation)
        Gym (is a Service Implementation)
    Games (Service with cat=26)
        Solitaire (is a Service Implementation)
        Pacman (is a Service Implementation)
        Scrubble (is a Service Implementation)