#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, a, r, t, u, v, c, d, b, s = 0, a1, r1;
  cin >> n;
  a = n / 51;
  s = s + a;
  r = n % 51;
  b = r / 15;
  s = s + b;
  t = r % 15;
  c = t / 14;
  s = s + c;
  u = t % 14;
  d = u / 5;
  s = s + d;
  v = u % 5;
  a1 = v / 2;
  s = s + a1;
  r1 = v % 2;
  s = s + r1;
  cout << s << endl;
  return 0;
}
