
Each graph is given as a sequence of numbers, starting with the number of vertices.
Then for each vertex, a list of the neighbours is given in clockwise order, plus a zero to end the list. Vertices are numbered starting with 1.
For example try this one and check what you get: 7 2 3 0 1 4 5 0 1 6 4 0 2 3 7 0 2 7 6 0 3 5 0 4 5 0.
The initial 7 means there are 7 vertices. Then the first vertex is adjacent to 2 and 3; 2 is adjacent to 1, 4 and 5; 3 is adjacent to 1, 6 and 4; and so on. Note the clockwise order of neighbours too. 