International Mathematical Olympiad selection process Olympiad. Although in principle students of the lower levels may be selected to go to the IMO, it generally takes many years before they can compete with students of the highest level or nivel superior. After the National Competition the twenty best students of each level are invited to the June Training Session where students undergo the IMO selection process. "Hrvatsko matematičko društvo" invites about 20 contestants who performed best at the national level (national level competition is separated by age) to the Croatian Mathematical Olympiad ("Hrvatska matematička olimpijada", HMO) which consists of 2 days, 4 problems each. The best
International Chemistry Olympiad seems appropriate, the selection process usually involves holding regional and national olympiad competitions. Many countries hold "training camps" for its top students, where mentors from the country give the students accelerated college-level courses in chemistry with an emphasis on the topics covered in that year's preparatory problems as well as practical training. It is agreed that such training programs must not exceed a total duration of two weeks but there are allegations every year that some countries exceed this limit by months or even years. Another concern is that some countries tend to bring the same students to the competition