import java.util.Scanner;
 
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int rx = sc.nextInt();
        int c=0;
        do{
            if(rx%5==0){
                rx-=5;
            }else if(rx%4==0){
                rx-=4;
            }else if(rx%3==0){
                rx-=3;
            }else if(rx%2==0){
                rx-=2;
            }
            c++;
        }while(rx>0);
        System.out.println(c);
    }
}

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12