We present a top-down lower bound method for depth 3 AND-OR-NOT circuits which is simpler than the previous methods and in some cases gives better lower bounds. In particular we prove that depth 3 AND-OR-NOT circuits that compute PARITY resp. MAJORITY require size a t least 20.6 18.. fi resp. 2°.849...fi. This is the first simple proof of a strong lower bound by a top-down argument for non-monotone circuits.