#include<stdio.h>
#include<stdlib.h>
typedef struct traffic {
    int data;
    struct traffic *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{
        root->right=insert(root->right,num);
    }

}

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

int main() {
    int size,i,num;
    scanf("%d",&size);
    if(size<0) {
        printf("Invalid input");
        return 0;
    }
    for(i=1;i<=size;i++)
    {
        scanf("%d",&num);
        root=insert(root,num);
    }
    postorder(root);
    return 0;
}