#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

  struct Tree {
    int elem;
    struct Tree *left;
    struct Tree *right;
  };

/* displays tree recursively */

void display (struct Tree *tree) {
  if (tree) {
    display (tree->left);
    printf ("The next element is %d\n", tree->elem);
    display (tree->right);
  }
}
  
/* inserts element into tree recursively */
struct Tree * insert (struct Tree *tree, int elem) {
  
  if (tree == NULL) {
    /* new element */
    tree = malloc (sizeof (struct Tree));
    tree->elem = elem;
  }
    
  if (elem < tree->elem) {
    /* insert into left branch */
    tree = insert (tree->left, elem);
  }
  else 
    /* insert on the right */
    tree = insert (tree->right, elem);
  
  return tree;
}

int main (int argc, char **argv) {
  
  int result;
  int elem;
  char *line = NULL;
  int length;
    
  struct Tree *tree = NULL;


  while (getline (&line, &length, stdin) > 1) {
    /* parse next line */
    /* pass over white space */
    while (line && isspace(line)) {
      line++;
    }
    /* read next integer */
    result = sscanf (line, "%d", elem);
    while (result != EOF) {
      if (result == 0) {
	fprintf (stderr, "Non-integer found, aborting !\n");
	exit (1);
      }

      /* skip integer just read */
      while (line && !isspace(line)) {
	line++;
      }
      
      /* insert element into tree */
      insert (tree, elem);
      while (line && isspace(line)) {
	line++;
      }
      result = sscanf (line, "%d", elem);

      
    }
    line = NULL;

    display (tree);
    tree = NULL;
  }
  return (0);
}