#include<stdio.h>
#include<stdlib.h>
struct Node {
    int data;
    struct node *prev, *next;
};
    int main() {
        int n,val,i;
        struct Node *head=NULL,*tail=NULL,*temp,*cur;
        if(scanf("%d",&n)!=1 || n<=0) {
            printf("Invalid input");
            return 0;
        }
        for(i=0;i<n;i++) {
            if(scanf("%d",&val)!=1) {
                printf("Invalid input");
                return 0;
            }
            temp=(struct Node*)malloc(sizeof(struct Node));
            temp->data=val;
            temp->next= NULL;
            temp->prev=tail;
            if (tail)
            tail->next=temp;
            else
            head=temp;
            tail=temp;
        }
        for(cur=head;cur!=NULL;cur=cur->next) {
            printf("%d",cur->data);
        }
        return 0;
    }