#include <iostream>
#include <cstdio>
using namespace std;

long long rez[1000005], n;

int cmmdc(int a, int b)
{
    if (b==0)
        return a;
    return cmmdc(b,a%b);
}

int main()
{
    freopen("fractii.in","r",stdin);
    freopen("fractii.out","w",stdout);
    rez[1]=1;
    rez[2]=3;
    rez[3]=7;
    rez[4]=11;
    rez[5]=19;
    cin >> n;
    for (int i=6; i<=n; ++i)
    {
        long long nr=0;
        for (int j=1; j<i; ++j)
        {
            if (cmmdc(i,j)==1)
            {
                ++nr;
            }
        }
        rez[i]=rez[i-1]+2*nr;
    }
    cout << rez[n];
    return 0;
}