#include "stdio.h"

using namespace std;

int main()
{
    int n,i,ok,nr(0),m;

    FILE* f=fopen("ciur.in","r");
    FILE* g=fopen("ciur.out","w");

    fscanf(f,"%i",&n);


    for(i=2;i<=n;i++)
    {
        ok=0;
        m=2;
        while(m<=7 && ok==0)
        {
            if(i%m==0 && i!=m)
                ok=1;

            if(m==2)
                m+=1;
            else
                m+=2;
        }

        if(ok==0)
            nr++;
    }

    fprintf(g,"%i",nr);

    fclose(f);
    fclose(g);

    return 0;
}