A school has four sections A, B, C, D of class x students. The results of half yearly and annual examinations are shown in the table given below:

Result	Number of students
	Section A	Section B	Section C	Section D
Students failed in both exams	25	22	18	20
Students failed in half yearly but passed in Annual exam	20	25	24	12
Students passed in half yearly but failed in Annual exam	12	15	8	10
Students passed in both exams	15	20	22	18

How many students are there in class X in the school?