#include <iostream>
#include <fstream>

using namespace std;

int main()
{
	freopen("DATA2.txt", "r", stdin);
	freopen("OUT2.txt", "w", stdout);

	int z = 5;
	while(z--){
	int count = 0;
	int n;
	cin >> n;
	for (int i = 1; i <= 1000; i++){
		for (int j = i; j <= 1000; j++){
			if (i*j <= n)
				count++;
			else if (i*j > n)
				break;
		}
	}
	cout << count << endl;
	}
}