#include <fstream>

using namespace std;

int cmmdc(int a, int b)
{
    if(a < b)
        return cmmdc(b, a);
    if(!b)
        return a;
    return cmmdc(a%b, b);
}

int main()
{
    ifstream in("fractii.in");
    ofstream out("fractii.out");
    int n;
    in >> n;
    int sum = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int j = i+1; j <= n; j++)
        {
            if(cmmdc(i, j) == 1)
                sum++;
                // out << i << "/" << j << endl;
        }
    }
    sum <<= 1;
    sum += 1;
    out << sum;
}