#include <bits/stdc++.h>
using std::cin;
using std::cout;
using std::endl;
int main() {
  int rem_distance, steps;
  cin >> rem_distance;
  steps = 0;
  while (rem_distance != 0) {
    if (rem_distance >= 5) {
      rem_distance -= 5;
      ++steps;
    } else if (rem_distance >= 4) {
      rem_distance -= 4;
      ++steps;
    } else if (rem_distance >= 3) {
      rem_distance -= 3;
      ++steps;
    } else if (rem_distance >= 2) {
      rem_distance -= 2;
      ++steps;
    } else if (rem_distance >= 1) {
      rem_distance -= 1;
      ++steps;
    }
  }
  cout << steps << endl;
  return 0;
}
