#include <iostream>
#include <vector>
#include <fstream>
using namespace std;

vector <int> v;
vector <int> ::iterator it1,it2;

ifstream fin("ciur.in");
ofstream fout("ciur.out");

int main()
{
    int n,i;

    fin>>n;

    v.push_back(2);
    v.push_back(3);


    for(i=5;i<=n;i++)
        if(i%2!=0&&i%3!=0)
            v.push_back(i);


    for(it1=v.begin()+2;it1!=v.end();it1++)
        for(it2=it1+1;it2!=v.end();it2++)
        {
            int x=*it1,y=*it2;

            if((*it2)%(*it1)==0)
                v.erase(it2),it2--;
        }

    fout<<v.size();








    return 0;
}