#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(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 preorder(Node *root)
{
    if(root!=NULL)
    {
        printf("%d ",root->data);
        preorder(root->left);
        preorder(root->right);
        
    }
}
int main()
{
    int n,i,num,;
    scanf("%d",&n);
    if(n<0)
    {
        printf("Invalid input");
        return 0;
    }
   
    if(val<0)
    {
        printf("Invalid input");
        return 0;
    }
    for(i=0;i<=n;i++)
    {
        scanf("%d",&num);
          root=insert(root,num);
       
    }
    
    preorder(root);
    
    return 0;
}