Are you *installing* Ubuntu or upgrading? If so, how did you upgrade? This looks like you tried to upgrade by manually editing your sources.list to point to Mantic, which isn't a supported method.
If so, you should be able to recover from the error by adding -o Dpkg::Options::="--force-overwrite" to the apt command you used to upgrade.
Are you *installing* Ubuntu or upgrading? If so, how did you upgrade? This looks like you tried to upgrade by manually editing your sources.list to point to Mantic, which isn't a supported method.
If so, you should be able to recover from the error by adding -o Dpkg::Options: :="--force- overwrite" to the apt command you used to upgrade.