#include<iostream>
#include<fstream>
using namespace std;
#define dragoste 2000001

int smerenie[dragoste];

int main ()
{
    ifstream fin("fractii.in");
    ofstream fout("fractii.out");

    int n,i,j;
    long long milostenie=0;

    fin>>n;
    //cout<<"VF";
    for (i=2; i<=n; ++i){
        smerenie[i] = i-1;
        //cout<<i<<" "<<n<<"\n";
    }
    //cout<<"VF";
    for ( i=2; i<=n; ++i)
        for ( j=2*i; j<=n; j+=i)
            smerenie[j] -= smerenie[i];
    //cout<<"VF";
    for ( i=1; i<=n; ++i)
        milostenie += smerenie[i];

    fout<<2*milostenie+1;
    return 0;
}