#include <iostream.h>
#include <fstream.h>
#define MAX 1000009
int v[MAX],n,i,j;
long long nr;
int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    f>>n;
    f.close();
    for (i=1;i<=n;i++)
        v[i]=i-1;
    for (i=2;i<=n;i++)
        {
        for (j=2*i;j<=n;j+=i)
            v[j]-=v[i];
        nr+=v[i];
        }
    nr=nr*2;
    nr++;
    g<<nr;
    g.close();
    return 0;
}