Smiley - Dream Girl chords

Hi.I'd like to share with you Smiley's "Dream Girl". The whole song contents of 4 
chords. Good Luck! :)
Intro: Am, G, Em, F
[ Tab from: http://www.guitaretab.com/s/smiley/322529.html ]
Am                 G
I’m sitting alone drinking alcohol
Em             F
I’m Writing a song about you
Am                   G
I know it’s so sad, maybe even mad
Em                       F
But I know what you’re doing behind my back

and it goes on and on 'till the end. Hope you liked it :)