#include<fstream.h>
ifstream in("fractii.in");
ofstream out("fractii.out");
int n,a[10000],s,p,k=0;
void beolvas(){
in>>n;
}
void init(){
for(int i=0;i<n;i++)
a[i]=1;
s=0;
}
int gcd(int e,int f){
if(e==0)return f;
return gcd(f%e, e);
}
short irred(int c, int b){
if(gcd(b,c)<2)return 1;
return 0;
}
void nez(int h){
if(irred(p,h))s++;
else for(int i=h-1;i<n;i+=h)a[i]=0;
}
int main(){
beolvas();
int j;
for(p=1;p<=n;p++){
init();
for(j=1;j<=n;j++)
if(a[j-1])nez(j);
k+=s;}
out<<k;
return 0;
}