#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(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 postorder(Node*root)
{
     if(root!=NULL){
    postorder(root->left);
    postorder(root->right);
    printf("%d",root->data);
     }
}
int main()
{
    int n,i,num;
    scanf("%d",&n);
    if(n<0)
    {
        printf("Invalid input");
        return 0;
    }
    for(i=1;i<=n;i++)
    {
        scanf("%d",&num);
        root=insert(root,num);
    }
    postorder(root);
}