Consider the simple interdomain topology shown below. In this exercise, we will compute the path from
AS1. For this, we need to build the routing tables of the other ASes in the topology.
Provide your answers as a comma-separated list of paths starting with the preferred one. For example, the answer:
indicates that the AS has learned two different paths. The preferred one is the one via
AS9 that has a length of 2 AS hops while the second path has a length of 3 AS hops. If there is no path, return 0 as your answer.