#include <fstream>
#define DIM 1000005
#define ll long long
using namespace std;

int n,s[DIM];

int main()
{
    ifstream fin("fractii.in");
    ofstream fout("fractii.out");
    fin>>n;
    ll ans=0;
    for(int i=1;i<=n;i++)
        s[i]=i-1;
    for(int i=2;i<=n;i++) {
        ans+=s[i];
        for(int j=2*i;j<=n;j+=i)
            s[j]-=s[i];
    }
    fout<<2*ans+1;
    return 0;
}