#include<stdio.h>
#include<stdio.h>

typedef struct node{
    int data;
    struct node *next;
    struct node *prev;
    
}Node;

Node *head,*tail;
void create(int num){
    Node *newnode =(Node*)malloc(1 *sizeof(Node));
    newnode -> data = next;
    newnode -> next = NULL;
    newnode -> prev =NULL;
    
    if(head ==NULL){
    head = newnode;
    tail = newnode;
    }else{
        tail -> next =newnode;
        newnode -> prev = tail;
        tail = newnode;
        
    }
    void deletion(){
        if(head==NULL){
            printf("Head is NULL");
            
        }else{
            tail->prev->next=NULL;
        }
    }
    void display(){
        Node *itr;
        for(itr=head;itr!=NULL;itr=itr->next){
            printf("%d",itr->data);
            
        }
        printf("/n");
    }
    int main(){
        int n,num,itr;
        scanf("%d",&n);
        if(n<0){
            printf("Invalid input");
            return 0;
            
        }
        for(itr=0;itr<n;itr++){
            scanf("%d",&num);
            create(num);
            
        }
        display();
        deletion();
        display();
        return 0;
    }
}