a team student city S send AllBerland Olympiad Informatics traditionally train all student buy ticket carriage consist n compartment compartment exactly people we know compartment contain student bore compartment contain student compartment fun entire tripthe student want swap people compartment student bore student to swap place person need convince necessary the student independently find necessary argument ask sympathetic conductor help the conductor use life experience persuade passenger switch place studenthowever conductor want waste time persuade wrong people want know minimum number people necessary persuade change place student your task find number after swap compartment student leave company student