Terrorist Two-Notrump/Economou Two Spades or Two NoTrump

An opening of two spades or two notrump shows a weak hand with a long suit (minimum of 6, but usually 7+ cards).

Response:
(a) if 2S was opening, bid 2nt to learn long suit
(b)i if 2nt was opening, bid 3C to learn long suit