E. Zeyad's Symmetric Functions
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

This problem is about the function $$$\textbf{f(x)=1/x}$$$. Given $$$l$$$ and $$$r (-10^{18} \le l \le r \le 10^{18})$$$. For each $$$\textbf{non-zero integer}$$$ $$$x_i (l \le x_i \le r)(x \neq 0)$$$,consider the triangle formed by:

1) The $$$X$$$-Axis

2) The $$$Y$$$-Axis

3) The tangent line to the curve $$$f(x) = 1/x$$$ at the point $$$(x_i , f(x_i))$$$

Find the sum of the areas of all such triangles.

Input

The only line of input contains two integers $$$l$$$ and $$$r (-10^{18} \le l \le r \le 10^{18})$$$.

(It's guaranteed that at least one of them doesn't equal 0)

Output

Print a single integer — the sum of the areas of the triangles.

Example
Input
1 1
Output
2
Note

The answer of the testcase, as in the image, is $$$(1/2) * 2 * 2 = 2$$$.