So let's try with set 1 by producing this circuit here. We do the same strategy. We put one arc here and make the arc out and in. Then we have all four possibilities, this arc in, this out, this in, this out and the fourth possibility. So, again we name this sets 5, 6, 7 and 8. Immediately we realise that 6, 7, and 8 don't have any possibilities of Hamiltonian circuits. So we are forced to work out number 5.