#include <bits/stdc++.h>
using namespace std;
int x;
int main() {
  cin >> x;
  for (int i = 1; 1; i++) {
    if (x == 0) {
      cout << i - 1 << endl;
      break;
    }
    if (x >= 5) {
      x = x - 5;
      continue;
    }
    if (x >= 4) {
      x = x - 4;
      continue;
    }
    if (x >= 3) {
      x = x - 3;
      continue;
    }
    if (x >= 2) {
      x = x - 2;
      continue;
    }
    if (x >= 1) {
      cout << i << endl;
      break;
    }
  }
}
