### Problem Statement

You are given a positive integer $N$.  
Find the number of quadruples of positive integers $(A,B,C,D)$ such that $AB + CD = N$.

Under the constraints of this problem, it can be proved that the answer is at most $9 \times 10^{18}$.

### Input

The input is given from Standard Input in the following format:

```
$N$
```

### Output

Print the answer.

### Constraints

-   $2 \leq N \leq 2 \times 10^5$
-   $N$ is an integer.

8

Here are the eight desired quadruples.

• (A,B,C,D)=(1,1,1,3)
• (A,B,C,D)=(1,1,3,1)
• (A,B,C,D)=(1,2,1,2)
• (A,B,C,D)=(1,2,2,1)
• (A,B,C,D)=(1,3,1,1)
• (A,B,C,D)=(2,1,1,2)
• (A,B,C,D)=(2,1,2,1)
• (A,B,C,D)=(3,1,1,1)