There is no identified middle school period although secondary education is divided into 2 phases. Following the first 3 years of general education students write for their lower certificate of education. Thereafter they enter either the arts or the science stream according to personal choice and teacher advice for 2 years. Once in that stream though, switching opportunities are limited. Following this latter period, they may complete 6th form, or study for a further 2 years for matriculation exemption.