Wrestling with two quantum Merlins. A bug has been found in the proof, the paper has been withdrawn. It has long been known, that if an all-powerful quantum wizard called Merlin can convince a quantum verifier called Arthur of some statement by sending a single quantum message, then a classical computer by itself can compute the same result in exponential time. In particular, the important. Problem in quantum chemistry is now known to be solvable in at most exponential time.