K. Count the squares
time limit per test
0.5 seconds
memory limit per test
12 megabytes
input
standard input
output
standard output

You are given a rectangle of dimensions $$$N\times M$$$ composed of $$$1\times 1$$$ squares. Your job is to count the number of squares inside that rectangle. The squares we are talking about can have any side length.

For example the number of squares inside a $$$2\times 3$$$ rectangle is $$$8$$$ : $$$6$$$ of side length $$$1$$$ and $$$2$$$ of side length $$$2$$$.

Input

The first and only line of the input contains two integers $$$1 \le N,M \le 10^6$$$

Output

Print a single integer, the answer to the problem

Examples
Input
2 3
Output
8
Input
4 4
Output
30