{ "id": 0 }
{ "id": 1, "parents": [] }
{ "id": 2, "parents": [ 0 ] }
{ "id": 3, "parents": [ 1, 2 ] }
{ "id": 4, "parents": [ 3 ] }
{ "id": 5, "parents": [ 3 ] }
{ "id": 6, "parents": [ 3 ] }
{ "id": 7, "parents": [ 4, 5, 6 ] }
{ "id": 8, "parents": [ 1, 2, 3, 4, 5, 6, 7, 0 ] }