#include<bits/stdc++.h>

using namespace std;

int arr[12000];

typedef struct TreeNode

{

int data,level;

TreeNode

*left,*right,*head;//attention

TreeNode

};

TreeNode *establish(int i,int n)

{

TreeNode *head=new TreeNode;

head->left=NULL;

head->right=NULL;

head->data=arr[i];

if(2i<=n+1&&arr[2i]!=0)

head->left=establish(2*i,n+1);

if(2i+1<=n+1&&arr[2i+1]!=0)

head->right=establish(2*i+1,n+1);

return head;

}

void preorder(TreeNode *head)

{

if(head==NULL)

return;

cout<<head->data<<" ";

preorder(head->left);

preorder(head->right);

}

void inorder(TreeNode *head)

{

if(head==NULL)

return;

inorder(head->left);

cout<<head->data<<" ";

inorder(head->right);

}

void afterorder(TreeNode *head)

{

if(head==NULL)

return;

afterorder(head->left);

afterorder(head->right);

cout<<head->data<<" ";

}

int main()

{

for(int i=1;i<=7;i++)

cin>>arr[i];

TreeNode *head=establish(1,7);

preorder(head);

cout<<endl;

inorder(head);

cout<<endl;

afterorder(head);

cout<<endl;

return 0;

}