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