#include<fstream>
using namespace std;

ifstream in("fractii.in");
ofstream out("fractii.out");

long p[1000009],n,i,j;long long t=0;

int main()
{
    in>>n;
    for(i=1;i<=n;i++)
        p[i]=i-1;
    for(i=2;i<=n;i++)
    {
        j=2*i;
        while(j<=n)
        {
            p[j]=p[j]-p[i];
            j=j+i;
        }
    }
    for(i=1;i<=n;i++)
        t=t+p[i];
    out<<2*t+1;

}