An endless checked page consists of square cells. The length of each side of the cell is k units. Smuidris drew a circle of radius r units on this page. The center of the circle was located on the intersection of two lines (in the middle of 4 cells). Then Smuidris painted all the cells that were crossed by the circle (that contained a part of the circle). (If the circle only touched a corner of the cell, Smuidris did not paint the cell).</p>

You are to write a program that for given values of natural numbers k and r (k < 30000, r < 30000) computes un outputs the number of cells painted by Smuidris.

입력 형식

출력 형식

예제 입력 1

1 5

예제 출력 1

28

예제 입력 2

3 7

예제 출력 2

20