#include <bits/stdc++.h>
using namespace std;
template <typename T1, typename T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& a) {
  os << "(" << a.first << ", " << a.second << ")";
  return os;
}
const char newl = '\n';
int main() {
  long long n;
  cin >> n;
  long long ans = 0;
  for (int i = 1; i < n; ++i) {
    ans += n / i;
    if (n % i == 0) ans--;
  }
  cout << ans << endl;
}
