#include <fstream.h>
#define MaxN 1000009

int i,j,n,v[MaxN];
long long nr;

int main()
{
    ifstream fin("fractii.in");
    fin>>n;
    fin.close();
    for(i=1;i<=n;i++)
        v[i]=i-1;
    for(i=2;i<=n;++i)
    {
        for(j=2*i;j<=n;j+=i)
            v[j]-=v[i];
        nr+=v[i];
    }

    nr*=2;
    nr++;
    ofstream fout("fractii.out");
    fout<<nr;
    fout.close();
    return 0;
}