## Description:

We define $$$f(x)$$$ as the number of numbers without a square factor within $$$x$$$. For example, when $$$x=10$$$, $$$f(x)=7$$$, because $$$1,2,3,5,6,7,10$$$ has no square factor, and $$$4,8,9$$$ each has a square factor.

Given a $$$x$$$, find the value of $$$f(x)$$$.

## Input:

An integer $$$x(1 \leq x \leq 10^{12})$$$.

## Output:

An integer $$$f(x)$$$.

## Sample Input:

10

## Sample Output:

7