#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 root;
}

Node*insert(Node*root,int num){
    if(root==NULL){
        return create(num);
    }
    else if(num < root->data){
        root->left=insert(root->left,num);
    }
    else if(num >root->data){
        root->right=insert(root->right,num);
    }
    return root;
    
}
Node*postorder(Node *root){
    
    root->left=postorder(root->left);
    root->right=postorder(root->right);
    printf("%d",root->data);
    
}

int main(){
    int n,num,va,i;
    if(!scanf("%d",&n) || n<0){
       printf("Invalid input");
       return 0;
    }
    for(int i=0;i<n;i++){
        scanf("%d",&num);
    }
    postorder(num);
    return 0;
}