You have two positive integers $*w*$ and $*h*$. Your task is to count the number of rhombi which have the following properties:

• Have positive area.
• With vertices at integer points.
• All vertices of the rhombi are located inside or on the border of the rectangle with vertices at points $(0, 0)$, $(*w*, 0)$, $(*w*, *h*)$, $(0, *h*)$. In other words, for all vertices $(*x*_{*i*}, *y*_{*i*})$ of the rhombus the following conditions should fulfill: $0 ≤ *x*_{*i*} ≤ *w*$ and $0 ≤ *y*_{*i*} ≤ *h*$.
• Its diagonals are parallel to the axis.

Count the number of such rhombi.

Let us remind you that a rhombus is a quadrilateral whose four sides all have the same length.

Input

The first line contains two integers $*w*$ and $*h*$ $(1 ≤ *w*, *h* ≤ 4000)$ — the rectangle's sizes.

Output

Print a single number — the number of sought rhombi.

Please do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use cin, cout streams or the %I64d specifier.

Note

In the first example there exists only one such rhombus. Its vertices are located at points $(1, 0)$, $(2, 1)$, $(1, 2)$, $(0, 1)$.