A school can represent up to three countries, ONE of which can be a security council country. Each country can have up to 11 delegates (one per committee) - except security council countries which can have one additional delegate, giving you a maximum of 34 delegates. While you can request specific countries, the three you end up with must be from different areas of the world and must not be countries your school has been assigned within the last two years. The order of the requests is taken into consideration, but is not the sole deciding factor. You'll get a reply within a few days telling you which countries you've been assigned.