// editor1
#include<stdio.h>
#include<stdlib.h>
typedef struct node{
    int data;
    struct node *left;
    struct node *right;
}nd;
nd *create(int num){
    nd *newnode=(nd*)malloc(sizeof(nd));
    newnode->data=num;
    newnode->left=NULL;
    newnode->right=NULL;
    return newnode;
}
nd *insert(nd *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 level(nd *root){
    if(root==NULL)
     return;
   nd *queue[100];
   int front=0,rear=0;
    queue[rear++]=root;{
    while(front<rear)
    nd *current=queue[front++];
    printf("%d ",current->data);
    if(current->left)queue[rear++]=current->left;
    if(current->right)queue[rear++]=current->right;
}
}
int main(){
    int n,num;
    nd *root=NULL;
    scanf("%d",&n);
    if(n<0){
        printf("Invalid input");
        return 0;
    }
    for(int i=0;i<n;i++){
        scanf("%d",&num);
        root=insert(root,num);
    }
    level(root);
    return 0;
}