// editor4
#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(1*sizeof(node));
    newnode->data=num;
    newnode->left=NULL;
    newnode->right=NULL;
    return newnode;
}

node*insert(node*root,int num){
    if(root!=NULL){
        retyurn 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;    
}
void postorder(node *root){
    if(root!=NULL){
        postorder(root->left);
        postorder(root->right);
        printf("%d",root->data);
    }
}
int main(){
    int n,itr,num;
    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;
}