#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int main()
{
    int i,n,j;
    long s;
    s=0;
    fin>>n;
    int x[n+5];
    fin.close();
    for (i=1;i<=n;i++)
    {
        x[i]=i-1;
    }
    for (i=1;i<=n;i++)
    {
        for (j=2*i;j<=n;j+=i)
        {
            x[j]=x[j]-x[i];
        }
    }
    for (i=2;i<=n;i++)
    {
        s=s+x[i];
    }
    s=s*2;
    s++;
    fout<<s;
    fout.close();
    return 0;
}