#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->datanum;
    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);
  else 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);
    }
}
void postOrder(Node *root)
{
    if(root!=NULL){
        postOrder(root->left);
        postOrder(root->right);
        printf("%d",root->data);
    }
}
void inOrder(Node *root)
{
    if(root!=NULL){
        inOrder(root->left);
        printf("%d",root->data);
        inOrder(root->right);
    }
}
int main()
{
    int size,num,itr;
    scanf("%d",&size);
    for(itr=1;itr<=size;itr++)
    {
        scanf("%d",&num);
        root=insert(root,num);
    }
    preOrder(root);
    return 0;
}