find out the primary packages installed

[BRINER Cedric <work@infomaniak.ch>]

hi,

How can I know which packages I asked to install. Instead of which 
packages are installed.

for exemple:
dpkg -l | wc
gives me about 1'000 of packaged installed

when I just invoke maybe 50 times: `aptitude install <the_package>'

In Fact, I'd like to have the list of packages that I install without 
the one who depends on them!

Thanks

Cedric BRINER