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Time Limit: 1.0 s

Memory Limit: 256.0 MB

Description

We say a positive integer x is balanced if there exist two positive integers a and b such that:

• a × b = x

• and |a − b| ≤ 1

In other words, x is the product of two equal or consecutive positive integers.

You are given a positive integer n. Your task is to count how many integers x satisfy the following conditions: 1 ≤ x ≤ n and x is balanced.

Input

A single integer n,(1 ≤ n ≤ \(10^9\))

Output

Print a single integer — the number of balanced integers between 1 and n, inclusive.

Sample

15

6

Explanation

Balanced numbers ≤ 15:

1 = 1 × 1

2 = 1 × 2

4 = 2 × 2

6 = 2 × 3

9 = 3 × 3

12 = 3 × 4

Total balanced numbers: 6