#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int count = 0;
  cin >> n;
  const regex neg("[124689]");
  const regex pos("3(57|75)|5(37|73)|7(35|53)");
  for (int i = 1; i < n; i++) {
    if (!regex_search(to_string(i), neg)) {
      if (regex_search(to_string(i), pos)) {
        count += 1;
      }
    }
  }
  cout << count << endl;
}
