Install Postgresql on Linux Mint 15 Olivia

Good Morning, im trying to install Postgresql 9.3 on Linux Mint 15, Olivia
distribution and I was not able to download it, according to a shell script
downloaded of

https://wiki.postgresql.org/wiki/Apt

The returned error was

*This script will enable the PostgreSQL APT repository on apt.postgresql.orgon
*
*your system. The distribution codename used will be olivia-pgdg.*
*
*
*Your system is using the distribution codename olivia, but olivia-pgdg*
*does not seem to be a valid distribution on*
*http://apt.postgresql.org/pub/repos/apt/dists/*
*
*
*We abort the installation here. Please ask on the mailing list for
assistance.*
*
*
*pgsql-pkg-debian(at)postgresql(dot)org*

I would appreciate any asistance in this subject, currently im using
Postgresql 9.1.3 that seems to be the latest version i was able to install.

Thanks in advance,

Guillermo Segalerba