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