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

Calculating dependencies... done!
[ebuild     U  ] sys-apps/file-5.36 [5.34]
[ebuild     U ~] app-misc/nnn-2.3 [2.2]
[ebuild     U  ] media-gfx/imagemagick-7.0.8.27 [7.0.8.25]
[ebuild  N     ] sys-apps/systemd-239-r4  USE="acl gcrypt kmod lz4 pam pcre resolvconf seccomp split-usr ssl sysv-utils -apparmor -audit -build -cryptsetup -curl -elfutils -gnuefi -http -idn -importd -libidn2 -lzma -nat -policy
kit -qrcode (-selinux) -test -vanilla -xkb" ABI_X86="(64) -32 (-x32)"
[ebuild  N     ] sys-apps/gentoo-systemd-integration-7
[ebuild   R    ] sys-apps/dbus-1.10.24  USE="systemd*"
[uninstall     ] sys-apps/sysvinit-2.91-r1
[blocks b      ] sys-apps/sysvinit ("sys-apps/sysvinit" is blocking sys-apps/systemd-239-r4)
[ebuild     U  ] www-misc/profile-sync-daemon-6.31 [5.45.1]
[blocks B      ] sys-apps/systemd ("sys-apps/systemd" is blocking sys-fs/eudev-3.2.5)
[blocks B      ] sys-fs/eudev ("sys-fs/eudev" is blocking sys-apps/gentoo-systemd-integration-7, sys-apps/systemd-239-r4)
[blocks B      ] sys-apps/gentoo-systemd-integration ("sys-apps/gentoo-systemd-integration" is blocking sys-fs/eudev-3.2.5)

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:


media-gfx/imagemagick:0

(media-gfx/imagemagick-7.0.8.27:0/7.0.8.27::gentoo, ebuild scheduled for merge) pulled in by
(no parents that aren't satisfied by other packages in this slot)

(media-gfx/imagemagick-7.0.8.25:0/7.0.8.25::gentoo, installed) pulled in by
media-gfx/imagemagick:0/7.0.8.25=[cxx] required by (sci-mathematics/octave-4.2.2:0/4.2.2::gentoo, installed)
^^^^^^^^^^^^


It may be possible to solve this problem by using package.mask to
prevent one of those packages from being selected. However, it is also
possible that conflicting dependencies exist such that they are
impossible to satisfy simultaneously.  If such a conflict exists in
the dependencies of two different packages, then those packages can
not be installed simultaneously.

For more information, see MASKED PACKAGES section in the emerge man
page or refer to the Gentoo Handbook.


* Error: The above package list contains packages which cannot be
* installed at the same time on the same system.

	(sys-apps/systemd-239-r4:0/2::gentoo, ebuild scheduled for merge) pulled in by
	sys-apps/systemd required by (virtual/service-manager-0:0/0::gentoo, installed)
	>=sys-apps/systemd-207 required by (sys-apps/gentoo-systemd-integration-7:0/0::gentoo, ebuild scheduled for merge)
sys-apps/systemd required by (www-misc/profile-sync-daemon-6.31:0/0::gentoo, ebuild scheduled for merge)
	sys-apps/systemd:0= required by (sys-apps/dbus-1.10.24:0/0::gentoo, ebuild scheduled for merge)
sys-apps/systemd required by (virtual/tmpfiles-0:0/0::gentoo, installed)

	(sys-fs/eudev-3.2.5:0/0::gentoo, installed) pulled in by
>=sys-fs/eudev-2.1.1 required by (virtual/udev-217:0/0::gentoo, installed)
	>=sys-fs/eudev-1.3:0/0[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (>=sys-fs/eudev-1.3:0/0[abi_x86_64(-)])
required by (virtual/libudev-232:0/1::gentoo, installed)


	For more information about Blocked Packages, please refer to the following
	section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

		https://wiki.gentoo.org/wiki/Handbook:X86/Working/Portage#Blocked_packages


		The following USE changes are necessary to proceed:
		(see "package.use" in the portage(5) man page for more details)
# required by sys-apps/systemd-239-r4::gentoo
# required by sys-apps/gentoo-systemd-integration-7::gentoo
		>=sys-apps/dbus-1.10.24 systemd

		Would you like to add these changes to your config files? [Yes/No] No

		* In order to avoid wasting time, backtracking has terminated early
		* due to the above autounmask change(s). The --autounmask-backtrack=y
		* option can be used to force further backtracking, but there is no
		* guarantee that it will produce a solution.