#include<iostream>
using namespace std;
struct bitNode
{
	char data;
	bitNode *lchild, *rchild;
} ;

void createBiTree ( bitNode  *&T )
{
	char ch;
	cin >> ch;
	if ( ch == '#' )
		T = nullptr;
	else
	{
		T = new bitNode;
		T->data = ch;
		createBiTree(T->lchild);
		createBiTree(T->rchild);

	}
}

void operation1(char ch)
{
	cout<<ch<<" ";
}

void preOrder(bitNode *T)
{
	if(T==nullptr)
		return;
	operation1(T->data);
	preOrder(T->lchild);
	preOrder(T->rchild);
}

void inOrder(bitNode *T)
{
	if(T==nullptr)
		return;

	inOrder(T->lchild);
	operation1(T->data);
	inOrder(T->rchild);
}

void postOrder(bitNode *T)
{
	if(T==nullptr)
		return;

	postOrder(T->lchild);
	postOrder(T->rchild);
	operation1(T->data);
}


int main()
{
	bitNode *T=nullptr;
	createBiTree(T);
	cout<<"前序 "<<endl;
	preOrder(T);
	cout<<endl;
	cout<<"中序 "<<endl;
	inOrder(T);
	cout<<endl;
	cout<<"後序 "<<endl;
	postOrder(T);
	return 0;
}