#include <fstream>
std::ifstream myread("fractii.in");
std::ofstream mywrite("fractii.out");
int gcd(int a, int b)
{
    if (a == 0)
        return b;
    return gcd(b % a, a);
}
int phi(unsigned int n)
{
    unsigned int result = 1;
    for (int i = 2; i < n; i++)
        if (gcd(i, n) == 1)
            result++;
    return result;
}
int main()
{
    int n;
    myread>>n;
    if(n==2)
        int rez=2*n;
    int rez=1;
    for(int i=2;i<=n;++i)
    {
        rez+=2*phi(i);
    }
    mywrite<<rez;
    return 0;
}