#include <iostream>
using namespace std;
ifstream cin("fractii.in");
ofstream cout("fractii.out");
int n;
int v[1000000];
int nr_div(int n)
{
    int div=2,s=1,p;
    while(n!=1)
    {
        p=0;
        while(n%div==0)
        {
            n/=div;
            p++;
        }
        if(p) s*=p+1;
        div++;
    }
    return s-1;
}
int main()
{
    cin>>n;
    int s=n,nr=n-1;
    for(int i=2;i<n;i++)
    {
        for(int j=i+1;j<=n;j++)
            if(j%i!=0) nr++;
    }
    cout<<2*nr+1;
    cin.close();
    cout.close();
    return 0;

}