#include<fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int i,j,N,v[1000000];
long long sir;
int main()
{
    for("i=2;i<=N;i++")
    {
        v[i]=i-1-v[i];
        for(j=2;j*i<=N;j++)
            v[i*j]=v[i]+v[i*j];
    }
    for(i=2;i<=N;i++)
        sir=sir+(long long)v[i]*2;
    sir++;
    fout<<sir;
    fin.close();
    fout.close();
    return 0;
}