// editor3
#include<stdio.h>
#include<stdlib.h>
typedef struct node{
    int data;
    struct node*prev;
    struct node*next;
}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{
        newNode->next=head;
        tail->next=newNode;
        tail=newNode;
    }
}
void display(){
    Node*i;
    for(i=head;i!=NULL;i=i->next){
        printf("%d",i->data);
    }
}
int main(){
    int size,i,num;
    scanf("%d",&size);
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    if(!scanf("%d",&num)){
        printf("Invalid input");
        return 0;
        create(num);
    }
   
   
    }
    display();
    return 0;
}