import java.util.Scanner;
public class Day_one {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        sc.close();
        int days = 0;
        while(n!=0) {
            n--;
            days++;
            if(days%7==0 && days!=0) {
                //System.out.println("Now boolean:"+String.valueOf(days%7==0));
                n+=6;
            }
            //System.out.println("Now Day:"+String.valueOf(days));
            //System.out.println("Now N:"+String.valueOf(n));
        }
        System.out.println(days);
    }
}