#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
  struct Node* left;
  struct Node* right;
  int num;
} Node;

void add(Node* newNode, Node* root) {
  if (root->num >= newNode->num) {
    if (root->right == NULL) {
      root->right = newNode;
    } else {
      add(newNode, root->right);
    }
  } else {
    if (root->left == NULL) {
      root->left = newNode;
    } else {
      add(newNode, root->left);
    }
  }
}

Node* head = NULL;
int arr[10000];
int n = 0;

void traverse(Node* node) {
  if (node->right != NULL && node->left != NULL) {
    arr[n] = node->num;
    n++;
  }

  if (node->right != NULL) {
    traverse(node->right);
  }

  if (node->left != NULL) {
    traverse(node->left);
  }
}

void sort() {
  int i, j, b;
  for (i = 0; i < n - 1; i++) {
    for (j = 0; j < n - i - 1; j++) {
      if (arr[j] > arr[j + 1]) {
        b = arr[j];
        arr[j] = arr[j + 1];
        arr[j + 1] = b;
      }
    }
  }
}

int main() {
  int b;
  Node* node;

  while (scanf("%d", &b) == 1) {
    if (b == 0) break;

    node = malloc(sizeof(Node));
    node->num = b;
    node->left = NULL;
    node->right = NULL;

    if (head == NULL) {
      head = node;
      continue;
    }

    add(node, head);
  }

  traverse(head);
  sort();

  int i;
  for (i = 0; i < n; i++) {
    printf("%d ", arr[i]);
  }
  printf("\n");

  return 0;
}