These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.07 s (backtrack: 0/20).

[ebuild  N     ] acct-group/at-0-r2::gentoo  0 KiB
[ebuild  N     ] acct-user/at-0-r2::gentoo  0 KiB
[ebuild  N     ] sys-process/at-3.2.5-r1::gentoo  USE="pam (-selinux)" 130 KiB

Total: 3 packages (3 new), Size of downloads: 130 KiB