/*@Unreal414 版权所有!!!*/
#include <bits/stdc++.h>
using namespace std;
int a[1000004];
int f(int N) {
	if (a[N] != -1) return a[N];
	int ans = 0;
	for (int i = 1; i <= N; i++)
		if (N % i == 0)
			ans++;
	a[N] = ans;
	return ans;
}
int main() {
	long long ans = 0;
	int n;
	memset(a, -1, sizeof(a));
	cin >> n;
	for (int i = 1; i <= n; i++) {
		ans += f(i);
	}
	cout << ans << "\n";
	return 0;
}