G = {
    'A' : ['B','D','E'] ,
    'B' : ['A','C'] ,
    'C' : ['B','D'],
    'D' : ['A','C','E'],
    'E' : ['A','D','G','F'],
    'F' : ['E','G'],
    'G' : ['E','F','H'],
    'H' : ['G']
}

sortie = []
file = []
file.append('A')