[(0,1),(1,2),(0,2),(1,3),(3,4),(4,5),(4,6),(5,6),(3,7),(2,7),(5,8),(6,9),(7,10)]
[(0,1),(1,2),(0,2),(2,3),(3,4),(3,5),(4,6),(5,6),(4,7),(6,7),(7,8),(1,9),(5,10)]
