#include<stdio.h>
#include<stdlib.h>
typedef struct travel{
    int data;
    struct travel*right,*left;
}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
        root->right=insert(root->right,num);
    return root;
}
void preorder(node* root){
    if(root!=NULL){
        printf("%d",root->data);
        preorder(root->left);
        preorder(root->right);
    }
}
int main(){
    int size,inum;
    scanf("%d",&size);
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    for(int i=0;i<=size;i++){
        scanf("%d",&num);
       root=insert(root,num);
    }
    preorder(root);
    return 0;
}