#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);
    else if(num=root->data)
    root->right=insert(root->right,num);
   
}
return root;
}
void preOrder() {
    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;
    }
    for(i=0;i<n;i++)
    {
        scanf("%d",&num);
        root=insert(root,num);
    }
    preOrder(root);
    return 0;
}