#include <bits/stdc++.h>
int main() {
  int input = 0;
  int temp = 0;
  int dist = 0;
  int steps = 0;
  scanf("%d", &input);
  temp = input;
  while (input != 0) {
    dist = 5;
    temp = input;
    while (input - dist < 0) {
      dist--;
    }
    input = input - dist;
    steps++;
  }
  printf("%d", steps);
}
