URI Online Judge | 1959

Regular Simple Polygons

By M.C. Pinto, UNILA BR Brazil

Timelimit: 1

In Euclidean geometry, a regular polygon is a polygon that is equiangular (all angles are equal in measure) and equilateral (all sides have the same length). A simple polygon is one that does not intersect itself anywhere. Below we can see various mosaics made of regular polygons.

You must write a program that, given the number and the length of sides of a regular polygon, show its perimeter.

Input

The input are two positive integers: N and L, which are, respectively, the number of sides and the length of each side of a regular polygon (3 ≤ N ≤ 1000000 and 1 ≤ L ≤ 4000).

Output

The output is the perimeter P of the regular polygon in a single line.

Input Samples Output Samples

3 1

3

9 8

72

1000000 1000

1000000000