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

int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    int n;
    f>>n;
    int i,j,t=n*2-1,k;
    int a[n+1][n+1]={0};
    bool c;
    for (i=2;i<=n;i++)
    {
        for (j=2;j<=n;j++)
        {
            if (a[i][j]==0)
            {
                k=2;
                c=true;
                while (k<=min(i,j)&&c)
                {
                    if (i%k==0&&j%k==0)
                    {
                        a[i][j]=1;
                        a[j][i]=1;
                        c=false;
                    }
                    k++;
                }
                if (c)
                {
                 t++;
                }
            }
        }
    }
    g<<t;
    g.close();
    f.close();
    return 0;
}