after thinking you wrote a III. I didn't know I can't count twigs.
The romans found that out to when they entered IIII, that's why they invented the V 
The V was invented for that precise reason, but at a push, i'm sure i could get away with IIII
but yes, it's VI or IV which deducts from which again?...
http://www.gsmarena.com/samsung_galaxy_s_iv_rumored_to_launch_on_march_15-news-5488.php