package Com;

import java.util.Scanner;

/*

 * 约瑟夫环问题，有n个人组成的圈，数到3的那个人出列，下个人继续从一开始

 */

public class Josephus {

    public static void main(String[] args) {

        Scanner s = new Scanner(System.in);

        int n = Integer.parseInt(s.nextLine());

        Node first = new Josephus().startRun(n );

        int count = 1;

        while(first.next != first) {

            first = first.next;

            count++;

            if(count == 3) {

                first.previous.next = first.next;

                first.next.previous = first.previous;

                first = first.next;

                count = 1;

            }

        }

        System.out.println("最后剩下来的数字为："+first.n);

    }

    public Node startRun(int n) {

        Node first = new Node();

        first.previous = null;

        first.n = n ;   //这里给链表赋值，倒叙

        Node current = first;

        Node last = first;

        while((--n)>0) {

            current.next = new Node();

            current = current.next;

            current.n = n;

            current.previous = last;

            last = current;

        }

        current.next = first;

        first.previous = current;

        return first;

    }

    class Node {

        int n ;

        Node next;

        Node previous;

    }

}