Insect wing venation identification

Hi,

I have an insect which I'd like to identify according to dichotomous key. Its a Diptera and the link shows its wing venation. I've tried to label the vein for identification purpose but i am not confident on my label, especially since the radius vein is confusing (is it R1, R2, R3, R4+5; or R1, R2+3, R4 & R5, and etc). Can any one help me for the labeling?