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

typedef struct TreeNode{
    int data;
    struct TreeNode *left;
    struct TreeNode *right;
}Node;

Node *root=NULL;

Node *create(int num){
    Node *newnode=(Node)malloc(sizeof(newnode));
    
    newnode->data=num;
    newnode->left=newnode->right=NULL;
    
    return newnode;
}


Node *inserBST(Node *root,int num){
    if(root==NULL){
        return create(num);
    }
    if(num<root->data){
        root->left=insertBST(root->left, num);
    }
    else{
        root->right=insertBST(root->right, num);
    }
    return root;
}


void postorder(Node *root){
    if(root==NULL){
        return NULL;
    }
    postorder(root->left);
    postorder(root->right);
    printf("%d", root->data);
}

int main(){
    int size, num;
    scanf("%d", &size);
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    for(int i=0; i<size; i++){
        scanf("%d", &num);
        root=insertBST(root,num);
    }
    
    postorder(root);
}