Debian 8にアップグレードした後、満たされない依存関係

Debian 7を8にアップグレードしたamd64後grep。この問題を解決するにはどうすればよいですか？

root@xyz:~# apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  grep
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
root@xyz:~# apt-get install grep
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 grep : PreDepends: libpcre3 (>= 1:8.35) but 1:8.30-5 is to be installed
E: Unable to correct problems, you have held broken packages.
root@xyz:~#