#include <fstream>
#include <string>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int n,i,j,t[1000001];
long long s;
int main()
{
    fin>>n;
    for(i=1;i<=n;i++)
        t[i]=i-1;
    for(i=2;i<=n;i++)
    {
        for(j=i*2;j<=n;j+=i)
            t[j]-=t[i];
        s+=t[i];
    }
    fout<<(s<<1)+1<< '\n';
    return 0;
}