#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);
    }
    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);
        preOrder(root);
    }
}

int main(){
    int n,num;
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        scanf("%d",&num);
        root = insert(root,num);
    }
    preOrder(root);
    
    
}