<n> <m>
<c11> <c12> .. <c1k1>
<c21> <c22> .. <c2k2>
..
<cm1> <c22> .. <cmkm>
Where n is the number of vertices, m is the number of constraints, ci is
the i:th constraint, and cij is the j:th vertex in the i:th constraint.
Say we have 10 vertices, and it is forbidden to include all of 0, 1 and 2
and it is forbidden to include both of 8 and 9. Then the input should look
as follows:
10 2
0 1 2
8 9