An unprotected chain consists of four net elements; ME1, NE2, NE3 and NE4.

Create an end-to-end VC4 path NE1-NE4 and add NE5 between NE2 and NE3 for capacity expansion.

The original configuration remains unchanged and no services are configured on the NE5.

In this case, the unprotected chain becomes NE1-NE2-NE5NE3-NE4, how many VC4 paths can be searched?