#include<stdio.h>
#include<stdlib.h>
typedef struct node
{
    int data;
    struct node *left, *right;
}Node;
Node *root=NULL;
Node *create(int num)
{
    Node *newNode=(Node*)malloc(1*sizeof(Node));
    newNode->data=num;
    newNode->left=NULL;
    newNode->right=NULL;
    return newNode;
}
Node *insert(Node *root, int num)
{
    if(root==NULL)
    return create(num);
    if(num<root->data)
    root->left=insert(root->left,num);
    if(num>root->data)
    root->right=insert(root->right,num);
    return root;
}
void inorder(Node *root)
{
    if(root=!NULL)
    {
        inorder(root->left);
        if(root->left==NULL && root->right==NULL){
        printf("%d ",root->data);
        
    }
    inorder(root->right);
}
}
int main()
{
    int n,i,num;
    scanf("%d",&n);
    if(n<0)
    {
        printf("Invalid input");
        return 0;
    }
    for(i=1;i<n;i++)
    {
    scanf("%d",&num);
    root=insert(root,num);
}
inorder(root);
return 0;
}