How to calculate this normal approximation problem?

A wine-taster claims that she can usually distinguish between domestic and imported wines. As a test, she is given 100 wines to test and correctly identifies 57 of them. What is the probability that she accomplished that good a record by pure guessing? That is, what is the probability of being correct 57 or more times out of 100 by pure guessing? (Use the normal curve to approximate the probability.)