#include<stdio.h>
#include<stdlib.h>
typedef struct Node{
    int data;
    struct Node*left;
    struct Node*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*buildTree(int arr[],int n,int i){
    if(i>=n || arr[i]=0){
        return NULL;
    }
    node*root=create(arr[i]);
    root->left=buildTree(arr,n,2*i+1);
    root->right=buildTree(arr,n,2*i+2);
    return root;
}

void postorder(node*root){
    if(root==NULL){
        return NULL
    }
    postorder(root->left);
    postorder(root->right);
    printf("%d",root->data);
}
void inorder(node*root){
    if(root==NULL){
        return NULL;
    }
    inorder(root->left);
    printf("%d",root->data);
    inorder(root->right);
}
int main(){
    int size;
    scanf("%d",&size);
    if(size<=0){
        printf("Invalid input");
        return 0;
    }
    int arr[size];
    for(int i=0;i<size;i++){
        scanf("%d",&arr[i]);
    }
    node*root=buildTree(arr,size,0);
    
    
    preorder(root);
    printf("\n");
    
    inorder(root);
    printf("\n");
    
    return 0;
}