#include <fstream>

using namespace std;

ifstream fin("fractii.in");
ofstream fout("fractii.out");

int n;
int numitor[1000005];
int numarator[1000005];

long long nrnumitor()
{
    numitor[1]=1;
    for(int i=2;i<=n;++i){
        numitor[i]=i-1;
    }
    for(int i=2;i<=n;++i){
        for(int j=i*2;j<=n;j+=i){
            numitor[j]-=numitor[i];
        }
    }
    long long s=0;
    for(int i=1;i<=n;++i){
        s+=numitor[i];
    }
    return s;
}

long long nrnumarator()
{
    numarator[1]=1;
    for(int i=2;i<=n;++i){
        numarator[i]=i-1;
    }
    for(int i=2;i<=n;++i){
        for(int j=i*2;j<=n;j+=i){
            numarator[j]-=numarator[i];
        }
    }
    long long s=0;
    for(int i=1;i<=n;++i){
        s+=numarator[i];
    }
    return s;
}

int main()
{
    fin >> n;
    fout << nrnumitor()+nrnumarator()-1;
    return 0;
}