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# Hyperprimes

**Timelimit: 1**

By Marcio T. I. Oshiro Brazil

Several mathematical discoveries of the middle ages are due to how famous Arabic mathematicians al-Khwarizmi, Omar Khayyam, and Sharaf al-Din al-Tusi and others. One of the results somewhat unknown is about the hyperprimes numbers. We say that a number is hyperprime if it has a prime number of divisors. Thus, for example, 25 hyperprime is, because it has three dividers. However 42 is not hyperprime, because it has 8 dividers.

Given an integer N, determine the number of hyperprimes in the interval [2, N].

The input consists of several instances and ends with the end of file (EOF).

Each instance consists of a single line containing a single integer **N** (2 ≤ **N** ≤ 2 × 10^{6}).

For each instance, print a line with the amount of hyperprimes in the interval [2, **N**].

Sample Input | Sample Output |

2 |
1 |