install postgreSQL in ubuntu 16.04

When following the Install PostgreSQL in Ubuntu in Ubuntu 16.04, got error as below:

 
$ apt-get install postgresql-9.6
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 adobereader-enu:i386 : Depends: libgtk2.0-0:i386 (>= 2.4) but it is not going to be installed
 postgresql-9.6 : Depends: postgresql-client-9.6
                  Depends: postgresql-common (>= 171~) but it is not going to be installed
                  Recommends: postgresql-contrib-9.6 but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

The suggested solution in the last line and a normal ubuntu upgrade do not solve the issue,  and the cmd below can fix it:

$sudo apt full-upgrade

After the fix, then can apt-get to install postgresql again. After install postgresql, then run cmd below to test it. A  user named postgres will be created automatically when install postgresql. Switch to this account first,

$sudo -i -u postgres

Now you can enter psql client:

$psql
postgres=#\q

Then you can login to the other postgresql database as below:

psql -h server -U user -d databasename -p port