SCCM 2012 R2 - Conditional Installation of Packages

Hi there!

I have 3 SCCM objects:

1. SCCM Package #1 to uninstall Application #1.
2. SCCM Package #2 to uninstall Application #2.
3. SCCM Application to install Application #3.
4. Application #1 and #2 are not installed on the same workstation, but need to be uninstalled prior to Application #3 installation.

I numerous attempts to accomplish that deployment I decided to go with the Task Sequence. The task sequence will include 3 tasks:

1. Task #N+1 to run SCCM Package #1 in order to uninstall Application #1 if Application #1 exists.
2. Task #N+2 to run SCCM Package #2 in order to uninstall Application #2 if Application #2 exists.
3. Task #N+3 to run SCCM Application in order to install Application #3.

What should I put into the Task Sequence if I know the GUIDs of the Applications #1 and #2?

Thank you very much!