Rectangles

There is a collection of $n$ squares, each with a side length of $1$. How many distinct rectangles can be formed using these squares?

Two rectangles are considered distinct if one cannot be rotated or moved to match the other. When constructing the rectangles, you cannot deform the squares or stack them on top of each other.

Input

One integer $n(1\le n\le 10^9)$.

Output

Print the number of distinct rectangles that can be formed using the squares.

Examples