#include<stdio.h>
#include<stdlib.h>
typedef struct Node{
    int data;
    struct Node *left;
    struct Node *right;
}node;

node *create(int num){
    node *newnode=(node*)malloc(sizeof(node));
    newnode->data=num;
    newnode->left=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 lvl(node* root,int n){
    if(root==NULL){
        return;
    }
    node *queue[100];
    int front=0,rear=0;
    queue[rear++]=root;
    while(front<rear){
        node *curr=queue[front++];
       printf("%d ",curr->data);
        if(curr->left){
            queue[rear++]=curr->left;
        if(curr->right)
            queue[rear++]=curr->right;
        }
    }
}
int main(){
    int n,num;
    node* 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);
    }
    lvl(root);
    return 0;
}