#include <bits/stdc++.h>
int main() {
  int x;
  scanf("%d", &x);
  int c = 0;
  while (x != 0) {
    if (x >= 5) {
      x = x - 5;
      c++;
    } else if (x >= 4) {
      x = x - 4;
      c++;
    } else if (x >= 3) {
      x = x - 3;
      c++;
    } else if (x >= 2) {
      x = x - 2;
      c++;
    } else if (x >= 1) {
      x = x - 1;
      c++;
    }
  }
  printf("%d", c);
  return 0;
}
