#include <iostream>
#include <fstream>
using namespace std;
ifstream in("fractii.in");
ofstream out("fractii.out");
bool v[1000001];
int n,sol;
long 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()
{    /*for(int i=2;i<=1000000;i++)
       if(v[i]==0)
        for(int k=2*i;k<=1000000;k=k+i)
          v[k]=1;*/
          in>>n;
for(int i=1;i<=n;i++)
    sol=sol+phi(i);
out<<2*sol-1;

    return 0;
}