tableTarif = dict( Nancy = [("Paris", 250), ("Toulouse", 300), ("Ajaccio", 450)],
                   Paris = [("Rome", 150), ("Madrid", 180), ("Londres", 120), ("Amsterdam", 170), ("Nancy", 250)],
                   Toulouse = [("Biarritz",100), ("Madrid", 120), ("Nancy", 300)],
                   Madrid = [("Barcelone", 120), ("Las_Palmas", 500), ("Paris", 180), ("Toulouse", 120)],
                   Londres = [("Amsterdam", 130), ("Edimbourg", 150),("Paris", 120)],
                   Rome = [("Paris", 150)],
                   Ajaccio = [("Nancy", 450)],
                   Amsterdam = [("Paris", 170), ("Londres", 130)],
                   Edimbourg = [("Londres", 130)],
                   Biarritz = [("Toulouse", 100)],
                   Barcelone = [("Madrid", 120)],
                   Las_Palmas = [("Madrid", 120)])
                   
                   
# liaisons a tester :
# entre "Nancy", "Toulouse"
# entre "Nancy", "Madrid"
# entre "Marseille", "Barcelone"
# entre "Las_Palmas", "Barcelone"
# entre "Nancy", "Barcelone"