8.2 Two Prime
(RankList for this Question)
Score: 30pts
Time Limit: 2.00 sec
Raju is a mathematician and has nothing to do on a Sunday. He has done a lot of research about prime numbers. So he decides to check if a number is Two-prime. A number is Two-prime if it has exactly two distinct prime divisors.

You are given an integer $$n$$. You have to find the total number of Two-prime numbers in the range $$1$$ to $$n$$, $$1$$ and $$n$$ inclusive.

Constraints
$$1 \leq n \leq 3000$$

Input Format
The test case contains a single integer $$n$$.

Output Format
You have to output a single integer on a new line, the number of Two-prime numbers in the range $$1$$ to $$n$$.

Example 1
Input:
10

Output:
2

Explanation:
There exist two numbers between 1 to 10 that are Two-prime. These numbers are 6 (prime divisors 2 and 3) and 10 (prime divisors 2 and 5).