#include <iostream>
#include <stdio.h>
using namespace std;
int v[1002];
FILE *f,*g;
int main()
{   int n,i,s,p,t=0;;
    f=fopen("ciur.in","r");
    g=fopen("ciur.out","w");
    fscanf(f,"%d",&n);
    for(i=2;i<=n;i ++)
    {
        s=1;
        p=2;
        while(s<=n)
        {
            s=p*i;
            v[s]=1;
            p++;
        }
    }
    for(i=2;i<=n;i++)
    {
        if(v[i]==0)
            t++;
    }
    fprintf(g,"%d",t);
    fclose(f);
    fclose(g);
    return 0;
}