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

int n,i,j,r;
int a[1000001];
long long k;
ifstream fi("fractii.in");
ofstream fo("fractii.out");

int main()
{
    fi>>n;
    for(i=1;i<=n;i++)
        a[i]=i-1;
    for(i=2;i<=n;i++)
        for(j=2*i;j<=n;j+=i)
        a[j]=a[j]-a[i];
    a[1]=1;
    for(i=1;i<=n;i++)
        k+=a[i];
    fo<<2*k-1;
}