Hello,
If you want to accept routes originated by your adjacent AS, and you don't care how many ASNs are prepended, use this regex:
set policy-options adjacent-as-only "<adjacent AS#>$"
If you want to accept routes originated by your adjacent AS, and you don't want to accept routes with more than 10 prepends, use this regex:
set policy-options adjacent-as-only-10prepends "<adjacent-AS#>{1,10}$"
Please PLEASE substitite <adjacent-AS#> with real ASN before using above regex.
HTH
Rgds
Alex