import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Queue;


public class card_trick {
    public static int count(int N){
        // Vasiot kod tuka
        ArrayQueue<Integer> spil = new ArrayQueue<Integer>(51);
        ArrayStack<Integer> drugite = new ArrayStack<Integer>(7);
        int brojac = 0;

        // Polnenje na spilot
        for(int i = 1; i <= 51; i++) {
            spil.enqueue(i);
        }


        while(true) {
            for(int i=1; i <= 7; i++) {
                int x = spil.dequeue();
                drugite.push(x);
            }
            brojac++;
            for(int i=1; i <= 7; i++) {
                int a = spil.dequeue();
                int b = drugite.pop();
                spil.enqueue(b);
                spil.enqueue(a);
            }

            if(drugite.isEmpty()&&spil.peek() == N)
                break;
        }


        return brojac;
    }

    public static void main(String[] args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in) );
        System.out.println(count(Integer.parseInt(br.readLine())));
    }

}

class ArrayQueue<E> implements Queue<E> {

    // Redicata e pretstavena na sledniot nacin:
    // length go sodrzi brojot na elementi.
    // Ako length > 0, togash elementite na redicata se zachuvani vo elems[front...rear-1]
    // Ako rear > front, togash vo  elems[front...maxlength-1] i elems[0...rear-1]
    E[] elems;
    int length, front, rear;

    // Konstruktor ...

    @SuppressWarnings("unchecked")
    public ArrayQueue (int maxlength) {
        elems = (E[]) new Object[maxlength];
        clear();
    }

    public boolean isEmpty () {
        // Vrakja true ako i samo ako redicata e prazena.
        return (length == 0);
    }

    public int size () {
        // Ja vrakja dolzinata na redicata.
        return length;
    }

    public E peek () {
        // Go vrakja elementot na vrvot t.e. pocetokot od redicata.
        if (length > 0)
            return elems[front];
        else
            throw new NoSuchElementException();
    }

    public void clear () {
        // Ja prazni redicata.
        length = 0;
        front = rear = 0;  // arbitrary
    }

    public void enqueue (E x) {
        // Go dodava x na kraj od redicata.
        elems[rear++] = x;
        if (rear == elems.length)  rear = 0;
        length++;
    }

    public E dequeue () {
        // Go otstranuva i vrakja pochetniot element na redicata.
        if (length > 0) {
            E frontmost = elems[front];
            elems[front++] = null;
            if (front == elems.length)  front = 0;
            length--;
            return frontmost;
        } else
            throw new NoSuchElementException();
    }

    public boolean contains(Object o) {
        // TODO Auto-generated method stub
        return false;
    }

    public Iterator iterator() {
        // TODO Auto-generated method stub
        return null;
    }

    public Object[] toArray() {
        // TODO Auto-generated method stub
        return null;
    }

    public Object[] toArray(Object[] a) {
        // TODO Auto-generated method stub
        return null;
    }

    public boolean remove(Object o) {
        // TODO Auto-generated method stub
        return false;
    }

    public boolean containsAll(Collection c) {
        // TODO Auto-generated method stub
        return false;
    }

    public boolean addAll(Collection c) {
        // TODO Auto-generated method stub
        return false;
    }

    public boolean removeAll(Collection c) {
        // TODO Auto-generated method stub
        return false;
    }

    public boolean retainAll(Collection c) {
        // TODO Auto-generated method stub
        return false;
    }

    public boolean add(Object e) {
        // TODO Auto-generated method stub
        return false;
    }

    public boolean offer(Object e) {
        // TODO Auto-generated method stub
        return false;
    }

    public E remove() {
        // TODO Auto-generated method stub
        return null;
    }

    public E poll() {
        // TODO Auto-generated method stub
        return null;
    }

    public E element() {
        // TODO Auto-generated method stub
        return null;
    }
}

interface Stack<E> {

    // Elementi na stekot se objekti od proizvolen tip.

    // Metodi za pristap:

    public boolean isEmpty ();
        // Vrakja true ako i samo ako stekot e prazen.

    public E peek ();
        // Go vrakja elementot na vrvot od stekot.

    // Metodi za transformacija:

    public void clear ();
        // Go prazni stekot.

    public void push (E x);
        // Go dodava x na vrvot na stekot.

    public E pop ();
        // Go otstranuva i vrakja elementot shto e na vrvot na stekot.
}

class ArrayStack<E> implements Stack<E> {

    // Stekot e pretstaven na sledniot nacin:
    //depth e dlabochinata na stekot, a
    // elems[0...depth-1] se negovite elementi.
    private E[] elems;
    private int depth;

    @SuppressWarnings("unchecked")
    public ArrayStack (int maxDepth) {
        // Konstrukcija na nov, prazen stek.
        elems = (E[]) new Object[maxDepth];
        depth = 0;
    }


    public boolean isEmpty () {
        // Vrakja true ako i samo ako stekot e prazen.
        return (depth == 0);
    }


    public E peek () {
        // Go vrakja elementot na vrvot od stekot.
        if (depth == 0)
            throw new NoSuchElementException();
        return elems[depth-1];
    }


    public void clear () {
        // Go prazni stekot.
        for (int i = 0; i < depth; i++)  elems[i] = null;
        depth = 0;
    }


    public void push (E x) {
        // Go dodava x na vrvot na stekot.
        elems[depth++] = x;
    }


    public E pop () {
        // Go otstranuva i vrakja elementot shto e na vrvot na stekot.
        if (depth == 0)
            throw new NoSuchElementException();
        E topmost = elems[--depth];
        elems[depth] = null;
        return topmost;
    }
}