#include <bits/stdc++.h>
int main(void) {
  long long n, temp, cnt = 0;
  int thr = 0, fiv = 0, sev = 0;
  scanf("%lld", &n);
  for (long long i = 1; i < n + 1; i++) {
    temp = i;
    while (i > 0) {
      if (i % 10 == 3 || i % 10 == 5 || i % 10 == 7) {
      } else {
        break;
      }
      i = (long long)i / 10;
      if (i == 0) {
        break;
      }
    }
    if (i == 0) {
      printf("i=%lld\n", temp);
      i = temp;
      while (i > 0) {
        switch (i % 10) {
          case 3:
            thr++;
            break;
          case 5:
            fiv++;
            break;
          case 7:
            sev++;
            break;
        }
        i = (long long)i / 10;
        if (i == 0) {
          break;
        }
      }
      if ((thr > 0 && fiv > 0) && sev > 0) {
        cnt++;
      }
      thr = 0;
      fiv = 0;
      sev = 0;
    }
    i = temp;
  }
  printf("%lld", cnt);
  return 0;
}
