are mainly focused on mathematics and either physics (MP), industrial sciences and technologies (TSI), physics and chemistry (PC), physics and engineering science (PSI), physics and technology (PT) and chemistry, physics and technology (TPC) . BCPST: biology, chemistry, physics, geology, and mathematics. Commonly called "Agro-Véto", these classes prepare students primarily for agricultural and veterinary schools, but also for schools in geology, hydrology, and forestry, as well as for research and teaching careers via the Écoles normales supérieures. Lettres: humanities, essentially for the Écoles normales supérieures (students can also compete to enter business schools, but represent a small minority of those admitted). There are two main sub-categories: "Lettres", in either "A/L" (with Ancient Greek and/or Latin) or LSH (with geography), and B/L (with mathematics and social sciences). Économique et commerciale: mathematics and economics. These prepare for the entrance exams to the French business schools, and are subdivided between science (mathematics) and economics tracks - a third track also exists for students with a "technological", i.e. applied background. Chartes: humanities, with an emphasis on philology, history and languages, named after the school École nationale des Chartes. By far the smallest prépa in number of students. Recruitment at baccalauréat level Some schools are accessible after a selection based on the grades of the two last years of lycée (High school) and/or the baccalaureate (High school diploma) results. For example, in engineering, the most attractive and selective ones are the seven schools composing the INSA network, but there are dozens of selective engineering schools accessible directly after the baccalaureate. Some famous ones are the three Universités de Technologie or the thirteen schools of Polytech Group. It is also possible to join these schools in third year after a preparatory class or university and then the recruitment is based on a contest or the student results. The top five of these engineering grandes écoles (among 77), according to the French magazine l'Etudiant magazine, are in 2021 INSA Lyon, UTC, UTT, INSA Toulouse, ESIEE Paris and ESILV - Paris-La Défense. Most of them simply include the two-year preparatory class in their program while others like INSA Toulouse chose the LMD to start the specialization earlier. Most students choose to get their licence, master or doctorate close to home. These years of preparation can be highly focused on the school program so students have a greater chance of succeeding in the admission exam or contest in their school