#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->next=NULL;
    newnode->prev=NULL;
    if(head ==NULL){
        head= newnode;
        tail= newnode;
    }else{
        newnode->pre=head;
        tail->next=newnode;
        tail=newnode;
    }
}
void display(){
    nd *itr;
    for(itr=head;itr!=NULL;itr->next){
        printf("%d",itr->data;)
    }
}
int main(){
    int n,num;
    scanf("%d",&n);
    if(n<=0){
        printf("Invalid input");
        return 0;
    }
    for(int i=0;i<n;i++){
        if(!scanf("%d",&num));{
            printf("Invalid input");
            return 0;
        }
        create(num);
    }
    display();
    return 0;
}