#include <fstream>
#include <string.h>
using namespace std;
ofstream fout("fractii.out");
ifstream fin("fractii.in");
int n,suma,s[1000005];
long long nrmax;
int main()
{
    fin>>n;
    s[1]=1;
    for(int i=2;i<=n;i++) s[i]=i-1;
    for(int i=2;i<=n;i++)
    {
        nrmax+=s[i];
        for(int j=2*i;j<=n;j+=i) s[j]-=s[i];
    }
    fout<<2*nrmax+1;
}