#include <fstream>

using namespace std;
int cmmdc (int a, int b)
{
    int r;
    while (r=a%b)
    {
        a=b;
        b=r;
    }
    return b;
}
int main()
{
    ifstream fin ("fractii.in");
    ofstream fout ("fractii.out");
    register int i;
    register int j;
    int n, k=1;
    fin >> n;
    for (i=1; i<n; ++i)
        for (j=i+1; j<=n; ++j)
            if (cmmdc(i,j)==1)
                ++k;
    fout << k*2-1;
    return 0;
}