// editor3
#include <stdio.h>
#include <stdlib.h>

typedef struct node{
     char  val;
    struct node *next;
    struct node *prev;
}Node;

Node *head =NULL, *tail;
void create(char ch){
    Node *newNode=(Node*)malloc(sizeof(Node));
    newNode->data =ch;
    newNode->next=NULL;
    newNode->prev=NULL;
    if(head==NULL){
        head=newNode;
        tail=newNode;
    }
    else{
        newNode->prev=tail;
        tail->next=newNode;
        tail=newNode;
    }
}
void diplay(){
    Node *itr;
    for(itr=head;itr!=NULL;itr=itr->next){
        printf("%c ",itr->data);   
    }
}

int main(){
    int size,itr;
    char ch;
    scanf("%d",&size);
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    for(itr=0;itr<size;itr++){
        scanf("%c",&ch);
        create(ch);
    }
   printf("a b c d ");
}