#include<bits/stdc++.h> using namespace std;

int main() { int n,x=0,y=0; cin>>n;

for(int i=1;i<=n;i++)
{
	for(int j=1;j<=n;j++)
	{
		if(i%j==0)
		x++;	
	}
	if(x%2==0)
	{
		y++;
		x=0;
	}
	else
	{
		x=0;
	}		
}
cout<<y;

}

#include <iostream>
#include <cmath>

using namespace std;

int main() {
    int n;
    cin >> n;
    int square_count = sqrt(n);
    int answer = n - square_count;
    cout << answer << endl;
    return 0;
}