#D4403. Almost Prime
Almost Prime
Almost Prime
A number is called almost prime if it has exactly two distinct prime divisors. For example, numbers 6, 18, 24 are almost prime, while 4, 8, 9, 42 are not. Find the amount of almost prime numbers which are between 1 and n, inclusive.
Input
Input contains one integer number n (1 ≤ n ≤ 3000).
Output
Output the amount of almost prime numbers between 1 and n, inclusive.
Examples
Input
10
Output
2
Input
21
Output
8
inputFormat
Input
Input contains one integer number n (1 ≤ n ≤ 3000).
outputFormat
Output
Output the amount of almost prime numbers between 1 and n, inclusive.
Examples
Input
10
Output
2
Input
21
Output
8
样例
10
2