CALCULATE

#define task "CALCULATE"
#include <iostream>
#include <cstdio>

using namespace std;

using ll = long long;
using ld = long double;

constexpr int N = 1e5 + 5;
ll n;

#define Cal(a, b) ((b) - (a) + 1)

void Solve()
{
    ll ans = 0;

    for (ll i = 1; i <= n / i; ++i)
        ans += Cal(n / (i + 1) + 1, n / i) * i;

    for (ll i = 1; i < n / i; ++i)
        ans += n / i;

    cout << ans << '\n';
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }
    while (cin >> n)
    {
        Solve();
    }
}