#include<stdio.h>
#include<stdlib.h>
typedef struct node {
    int data;
    struct node *left,*right;
}Node;
Node *root=NULL;
int n;
Node* create(int num)
{
    Node *newnode=(Node*)malloc(sizeof(Node));
    newnode->data=num;
    newnode->left=NULL;
    newnode->right=NULL;
    return newnode;
}
Node *insert(int arr[],int i,int num)
{
    Node *root=NULL;
    if(i<n &&arr[i]!=-1)
    {
        root=newnode(arr[i]);
        root->left=insert(arr,2*i+1,n);
        root->right=insert(arr,2*i+1,n);
    }
    return root;
}
void printleafnodes(Node *root)
{
    if(root==NULL)
    {
        return ;
        
    }
    if(root->left==NULL&&root->right==NULL)
    {
        printf("%d ",root->data);
    }
    printleafnodes(root->left);
    printleafnodes(root->right);
}

int main()
{
    int n,itr,num;
    scanf("%d",&n);
    int arr[n];
    for(itr=0;itr<n;itr++)
    {
        scanf("%d",&arr[i]);
        root=insert(arr,0,n);
        
    }
    printleafnodes(root);
}