Education in Pakistan is divided into six main levels: nursery (preparatory classes); primary (grades one through five); middle (grades six through eight); matriculation (grades nine and ten, leading to the secondary certificate); intermediate (grades eleven and twelve, leading to a higher secondary certificate); and university programmes leading to graduate and postgraduate degrees. There is a network of private schools that constitutes a parallel secondary education system based on a curriculum set and administered by the Cambridge International Examinations of the United Kingdom. Some students choose to take the O-level and A level exams conducted by the British Council. According to the International Schools Consultancy, Pakistan has 439 international schools.