#include <stdio.h>

struct list {
   float val;
   list* next;
   list* prev;
};

int main()
{
   int n;
   scanf_s("%d", &n);

   list* head = new list;
   head->prev = NULL;

   float c;
   scanf_s("%f", &c);
   head->val = c;

   list* temp = head;
   for (int i = 2; i <= n; i++)
   {
      scanf_s("%f", &c);
      temp->next = new list;
      temp->next->val = c;
      temp->next->prev = temp->next;
      temp = temp->next;
   }
   temp->next = head;
   head->prev = temp;


   return 0;
}