Shortcut key to get to beginniing of line in R?

This is a generalize question: basically, say you are typing a long  
line of
command in R console, and then you realize you forgot to add  
something in
the beginning, is there a way to get to the beginning of the line  
without
pressing the "left" key on the keyboard and waiting for the cursor  
to get to
the beginning, or using the mouse?

I'm using windows version of R.