What is the correct motor placement for my ar drone 2.0?

I replaced my central cross and when i took out the four motors on the broken one, I did not keep them in the same order as they were, but mistakingly got them mixed up. Now my drone wont take of or it flies eractically a few seconds, then crashes. I've tried to look at the motors but dont see any markings. Are the motors all the same and turn the same direction? please help