import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;


 class card_trick{
    public static int count(int N){
        Stack<Integer> sedum=new Stack<Integer>();
        Queue<Integer> spil=new LinkedList<Integer>();
        int Karta=1;
        int counter=0;
        while(Karta!=52)
        {
            spil.add(Karta++);
        }
        while(spil.peek()!=N)
        {		counter++;
            for (int i=1;i<=7;i++)
            {
                sedum.push(spil.poll());
            }
            for (int i=1;i<=7;i++)
            {
				spil.add(sedum.pop());
                spil.add(spil.poll());
            }
        }
        return counter;
    }
    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())));
    }
}