3-ta

let input = [
   'Append Steven',
   'Examine 1',
   'Find Ina',
   'Append Niki',
   'Insert 0 Peter',
   'Append Nadya',
   'Insert 3 Grigor',
   'Examine 5',
   'Append Asya',
   'Insert 4 Steven',
   'Append Steven',
   'Find Asya',
   'Find Steven',
   'Examine 3',
   'Find Peter',
   'Examine 4',
   'Find Steven',
   'Insert 1 Ina',
   'End'

];
let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);
// Code

let myResult = []

class LinkedListNode {
   constructor() {
       this.value = null;
       this.next = null;
       this.prev = null;
   }
}

 class WaitingList {
    head =null
    tail =null
    count = 0
    constructor(){
      this.nameMap = new Map();
    }



    addFirst(value) {
      const node = new LinkedListNode();
      node.value = value
      if(!this.head){
         this.head=node;
         this.tail = node;
      } else {
      node.next = this.head;
      this.head.prev = node;
      this.head = node;
      }
      this.count++;
      const count = this.nameMap.get(value) || 0;
      this.nameMap.set(value, count+1);
      myResult.push('OK');

    }

    append(value) {
      const node = new LinkedListNode();
      node.value = value
      if(!this.head) {
         this.head = node;
      } else {
         this.tail.next = node;
         node.prev = this.tail;
      }
      this.tail = node;
      this.count++;
      const counter = this.nameMap.get(value) || 0;
      this.nameMap.set(value, counter+1);
      myResult.push('OK');
    }

    removeFirst(){

      if(this.count === 1){
         const val = this.head.value;
         this.head = null;
         this.tail = null;
         this.count--;
         return val;
      } else {
      const val = this.head.value;
      this.head = this.head.next;
      this.head.prev = null;
      this.count--;
      return val;
      }
    }

    removeLast() {

      if(this.count === 1){
         const val = this.tail.value;
         this.head = null;
         this.tail = null;
         this.count--;
         return val;
      } else {
         const val = this.tail.value;
         this.tail.prev.next = null;
         this.count--;
         return val;
      }
    }


    insertBefore(node,val){
      const newNode = new LinkedListNode();
      newNode.value = val
      if(node === this.head){
         newNode.next = this.head;
         this.head.prev = newNode;
         this.head = newNode;
         this.count++;
      } else {
      node.prev.next = newNode;
      newNode.next = node;
      node.prev = newNode;
      this.count++;
      }
      const counter = this.nameMap.get(val) || 0;
      this.nameMap.set(val, counter+1);
      myResult.push('OK')

    }


    // new methods

    insert(pos, name) {
      if(pos < 0 || pos  > this.count) {
         myResult.push('Error');
      } else {
         // const counter = this.nameMap.get(name) || 0;
         // this.nameMap.set(name, counter+1);
         if(Number(pos) === 0){
            this.addFirst(name)
         } else if (Number(pos) === this.count) {
            this.append(name)
         } else {
            let ref = this.head
            for (let i = 1; i<= pos; i++){
               ref = ref.next
            }
            this.insertBefore(ref, name)
         }

      }
   }

      find(name){
         let a = this.nameMap.get(name) || 0;
         myResult.push(a)
      }

      examine(val){
         if(val > this.count){
           myResult.push('Error')
         } else {
         let outPut = [];
         for (let i = 1; i <= val;i++){
            let patient = this.removeFirst()
            let counter = this.nameMap.get(patient);
            if (counter === 1){
               this.nameMap.delete(patient)
            } else {
               this.nameMap.set(patient, counter-1)
            }
            outPut.push(patient)
         }
         myResult.push(outPut.join(' '));
         }
      }

}




const list = new WaitingList();
outer:
while (true){
   command = gets().split(' ')
   let methodName = command[0].toLowerCase()
   switch(methodName) {
      case 'end':
         break outer;
      case 'append':
         list.append(command[1]);
         break;
      case 'insert':
         list.insert(command[1], command[2]);
         break;
      case 'find':
         list.find(command[1]);
         break;
      case 'examine':
         list.examine(command[1]);
   }

}
for (const el of myResult){
   console.log(el);
}