$ sudo apt-get -f install
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following extra packages will be installed:
  firefox
Suggested packages:
  latex-xft-fonts firefox-gnome-support
The following NEW packages will be installed:
  firefox
0 upgraded, 1 newly installed, 0 to remove and 352 not upgraded.
214 not fully installed or removed.
Need to get 0 B/24.8 MB of archives.
After this operation, 55.2 MB of additional disk space will be used.
Do you want to continue [Y/n]? y
(Reading database ... 106348 files and directories currently installed.)
Unpacking firefox (from .../firefox_20.0+build1-0ubuntu0.12.10.3_amd64.deb) ...
dpkg: error processing /var/cache/apt/archives/firefox_20.0+build1-0ubuntu0.12.10.3_amd64.deb (--unpack):
 trying to overwrite '/usr/share/applications/firefox.desktop', which is also in package kubuntu-firefox-installer 12.04ubuntu1
No apport report written because MaxReports is reached already
                                                              Processing triggers for man-db ...
Errors were encountered while processing:
 /var/cache/apt/archives/firefox_20.0+build1-0ubuntu0.12.10.3_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)