#include <fstream>

using namespace std;
ifstream in ("fractii.in");
ofstream out ("fractii.out");
int v[1000005];
int main()
{
    int n,i,j;
    long long s=0;
    in>>n;
    for(i=2;i<=n;i++)
    {
        v[i]=i-1;
    }
    for(i=2;i<=n;i++)
    {
        s=s+v[i];
        for(j=2*i;j<=n;j=j+1)
        {
            v[j]=v[j]-v[i];
        }
    }
    out<<s*2+1;
    return 0;
}