#include
     
      using namespace std;int f;typedef struct BiTNode{	int data;	struct BiTNode *lchild,*rchild;}BiTNode,*BiTree;void visit(BiTree T){	if(T->data!=NULL)	{		if(f==1)		{			cout<<" "<
      
       data;		}		else		{			cout<
       
        data;			f=1;		}	}}void insert(BiTree &T,int key){	if(T==NULL)	{		T=new BiTNode;		T->lchild=T->rchild=NULL;		T->data=key;		return ;	}	if(key
        
         data)		insert(T->lchild,key);	else		insert(T->rchild,key);}void InOrder(BiTree T){	if(T)	{		InOrder(T->lchild);		visit(T);		InOrder(T->rchild);	}}int main(){	int m,i,n;	BiTree T;	while(cin>>m)	{		T=NULL;		for(i=0;i
         
          >n;		    insert(T,n);		}		f=0;		InOrder(T);		cout<<"\n";	}	return 0;}