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