baekjoon2164

const fs = require("fs");
const filePath =
  process.platform === "linux" ? "/dev/stdin" : __dirname + "/example.txt";
let input = fs.readFileSync(filePath).toString();
  
  class Node {
    constructor(data) {
      this.data = data;
      this.next = null;
    }
  }
  
  class Queue {
    constructor() {
      this.head = null;
      this.rear = null;
      this.size = 0;
    }
  
    enQueue(data) {
      const newNode = new Node(data);
  
      if (!this.head) {
        this.head = newNode;
        this.rear = newNode;
      } else {
        this.rear.next = newNode;
        this.rear = newNode;
      }
  
      this.size++;

      return newNode;
    }
  
    deQueue() {
      if (!this.head) {
        return null;
      }
  
      const removeNode = this.head;
      this.head = this.head.next;
      if (!this.head) {
        this.rear = null;
      }
  
      this.size--;
  
      return removeNode.data;
    }

  }

  const Q = new Queue();
  
  for(let i = 1; i<= input; i++){
    Q.enQueue(i);
  }

  while(Q.size > 1){
    Q.deQueue();
    Q.enQueue(Q.head.data);
    Q.deQueue();
  }

  console.log(Q.head.data)