Помогите ответить на вопрос when do you have your winter holidays?

The schedule of vacation for pupils of Junior, middle and senior level is in direct proportion to the allocation of study time. In the classic version, by quarters, winter holidays at school start on December 26, 2015 and ends on January 10, 2016. In the part of educational institutions the academic year is divided into trimesters, for the pupils of such schools has as much as two period of freedom from compulsory lessons, homework during the winter. The first school holidays they will run from 31 December 2015 to 10 January 2016 inclusive. The second week of winter falls on February, 15 and 23 number, to class, students will start on February 24