#include<stdio.h>
#define maxsize 100
typedef struct node{
  char data;
  struct node *lchild,*rchild;
 }bt;
typedef struct q{
  bt *data[maxsize];
  int front,rear;
 }queue;

createbt(bt **T)
 {
  char ch;
  scanf("%c",&ch);
  if(ch==' ')*T=NULL;
   else{
   *T=(bt *)malloc(sizeof(bt));
   (*T)->data=ch;
   createbt(&((*T)->lchild));
   createbt(&((*T)->rchild));
   }
 }


leveltrav(bt *t)
{
 queue qu; bt *temp;
 qu.front=0;
 qu.rear=0;
 qu.rear++;
  if(!t)return 1;
  qu.data[qu.rear]=t;
  while(qu.front!=qu.rear){
   qu.front=(qu.front+1)%maxsize;
   temp=qu.data[qu.front];
   printf("%c ",temp->data);
   if(temp->lchild){
     qu.rear=(qu.rear+1)%maxsize;
     qu.data[qu.rear]=temp->lchild;
    }
    if(temp->rchild){
     qu.rear=(qu.rear+1)%maxsize;
     qu.data[qu.rear]=temp->rchild;
    }  
  } 
}
main()
{
 bt *h;
 createbt(&h);
 leveltrav(h);
}