#include<iostream.h>
#include<fstream.h>
#include<stdio.h>
long long a[10000][10000];
//ifstream p("fractii.in");
//ofstream v("fractii.out");
void gen(int n){
int i,j,z;
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
for(z=2;z<=n;z++)
a[i*z][j*z]=-1;
}
int nr(int n){
int s=0;
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
if(a[i][j]!=-1)s++;//cout<<i<<" "<<j<<endl;
return s;
}
int main(){
int n;
freopen("fractii.in","r",stdin);
//freopen("fractii.out","w",stdout);
cin>>n;
gen(n);
freopen("fractii.out","w",stdout);
cout<<nr(n);
//getch();
//clrscr();
return 0;
}