Knights always tell the truth and Knaves always lie.
In a group of six people, the following statements are made:
- Alice says, "None of us are Knights."
- Bob says, "Exactly two of us are Knights."
- Cathy says, "At least three of us are Knights."
- Dave says, "At most three of us are Knights."
- Evelyn says, "Exactly five of us are Knights."
- Frank says, "Exactly one of us is a Knight."
How many Knights are there?