For example, if you choose the bachelor's degree in “Business Administration” and “Business Informatics”, then you pass the Russian language and Mathematics exams only one time. If, for example, you choose the programmes "Economics" and "Law", then you will have to take the Russian language (once), as well as Mathematics (for "Economics") and History (for "History"). That is, three exams in total.
You can test your abilities by going through trial entrance tests on different subjects (https://perm.hse.ru/admissions/ba/test).