#include<stdio.h>
#include<stdlib.h>
typedef struct node{
    int data;
    struct node*next;
    struct node*prev;
}Node;
Node *head=NULL,*tail;

void create (int num){
    Node *newNode=(Node*)malloc(sizeof(Node));
    newNode->data=num;
    newNode->prev=NULL;
    newNode->next=NULL;
    if(head==NULL){
        head=newNode;
        tail=newNode;
    }
    else{
        tail->next=newNode;
        newNode->prev=tail;
        tail=newNode;
        }
}       
        
  void display(){
      Node*itr;
      for(itr=head;itr!=NULL;itr=itr->next){
          printf("%d ",itr->data);
      }
  } 
  int main(){
      int size,iter,num;
      scanf("%d",&size);
      if(size<0){
          printf("Invalid input");
          return 0;
      }
      for(iter=0;iter<size;iter++){
          printf("%d",data);
      create(num);
      }
      display();
      return 0;
  }