#include <bits/stdc++.h>
using namespace std;
int main() {
  long N;
  cin >> N;
  long ans = 0;
  long i;
  int chk[3] = {0, 0, 0};
  int wa;
  long tmp;
  if (N < 357)
    ans = 0;
  else {
    for (i = 357; i <= N; i += 2) {
      chk[0] = 0;
      chk[1] = 0;
      chk[2] = 0;
      wa = 1;
      tmp = i;
      while (tmp > 0) {
        switch (tmp % 10) {
          case 3:
            chk[0]++;
            break;
          case 5:
            chk[1]++;
            break;
          case 7:
            chk[2]++;
            break;
          default:
            wa = 0;
            break;
        }
        tmp /= 10;
      }
      if (chk[0] > 0 && chk[1] > 0 && chk[2] > 0 && wa == 1) ans++;
    }
  }
  cout << ans;
}
