#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    int n,i,j,ir=0;
    f>>n;
    ir=n;
    for(i=2;i<=n;i++){
        ir+=(n/i) + 1;
    }
    cout<<ir;
}