Help!!! Get advertisers, or Publishers first????

I'm starting an ad network and wondering what is best to get in first.... advertisers or publishers??

im wondering because if publisher sign up first they wont get paid out until i get advertisers in = pointless

if i get advertisers first, then they dont have anything to advertise on = pointless...

so is there a way to get both in , or which would you suggest signing up first

i have resources