Why is my steering pulling to the right on my Nissan Maxima?

[batman]

My steering pulls to the right when i steer to the right...but when i steer to the left it stops pulling untill i steer back to the right. What is the prob?? Thanks

 

[lksproodle51]

Low tire pressure on the right side.

 

[austinggrant]

alignment, maybe a flat tire