Education in Poland is compulsory between ages 6-18. Public schools are free of charge. Children first attend kindergarten from ages 3-6, then primary school from ages 7-12 where they are not divided into subjects in the early years. From ages 13-15 students attend gymnasium where they study core subjects. Students can then attend vocational or academic high schools. Teachers are required to have a university degree and promote through four degrees over 12 years for higher pay and job security.