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


int main(){
    
    long long i,j,counter,a[1000000];
    long long b[1000000];
    ifstream in_file;
    ofstream out_file;
    in_file.open("fractii.in");
    out_file.open("fractii.out");
    long n;
    
     
    
    in_file>>n;
   
    for(i=1;i<=n;i++){
                   a[i]=i;
                   b[i]=1;
           }
    
    long long aux;
    long long nou;
    
    for(j=2;j<=n;j++)  {
                       aux=2;
                       nou=aux;
                       while(nou<=n){
                                     
                                     nou=aux*j;
                                     if(nou>n)
                                              break;
                                     b[j]++;
                                     b[nou]++;
                                     aux++;
                                     
                                     }
                       }
                       
    counter = n;
    
    for(i=2;i<=n;i++)
                     counter=counter + (n-b[i]);
    out_file<<counter<<endl;
    
    return 0;
                                                    
    
    
    
    }