#include<stdio.h>
#include<stdlib.h>

typedef struct node{
    int data;
    struct node *left;
    struct node *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);
    }else if(num > root->data){
        root->right=insert(root->right,num);
        return root;
    }
    
}
void preorder(Node *root){
    if(root!=NULL){
        preorder(root->left);
        postorder(root->right);
        printf("%d",root->data);
    }
}

int main(){
    int size,itr,num;
    scanf("%d",&size);
    for(itr=11;itr<=size;itr++){
        scanf("%d",&num);
        root = insert(root,num);
    }
    preorder(root);
    return 0;
}