Problem Statement

You are given an integer N. Find the number of pairs (i,j) of positive integers at most N that satisfy the following condition:

• $i \times j$ is a square number.

Input

Input is given from Standard Input in the following format:
N

Output

Print the answer.

Constraints

• $1 \le N \le 2 \times 10^5$
• N is an integer.

Sample Input 1

4

Sample Output 1

6

The six pairs (1,1),(1,4),(2,2),(3,3),(4,1),(4,4) satisfy the condition.
On the other hand, (2,3) does not$, since 2 \times 3 =6$ is not a square number.

Sample Input 2

254

Sample Output 2

896

见题面 Input 部分

见题面 Output 部分