import time
import random
import csv
import os
import sys

sys.setrecursionlimit(30000)

def ll_insert(head, name, phone):
    curr = head
    while curr is not None:
        if curr['name'] == name:
            curr['phone'] = phone
            return head
        curr = curr['next']
    new_node = {'name': name, 'phone': phone, 'next': head}
    return new_node


def ll_find(head, name):
    curr = head
    while curr is not None:
        if curr['name'] == name:
            return curr['phone']
        curr = curr['next']
    return None


def ll_delete(head, name):
    if head is None:
        return None
    if head['name'] == name:
        return head['next']
    prev = head
    curr = head['next']
    while curr is not None:
        if curr['name'] == name:
            prev['next'] = curr['next']
            return head
        prev = curr
        curr = curr['next']
    return head


def ll_list_all(head):
    entries = []
    curr = head
    while curr is not None:
        entries.append((curr['name'], curr['phone']))
        curr = curr['next']
    entries.sort(key=lambda x: x[0])
    return entries

    def _hash(name, bucket_count):
    h = 0
    for ch in name:
        h = (h * 31 + ord(ch)) % bucket_count
    return h


def ht_create(bucket_count=2000):
    return [None] * bucket_count


def ht_insert(buckets, name, phone):
    idx = _hash(name, len(buckets))
    buckets[idx] = ll_insert(buckets[idx], name, phone)


def ht_find(buckets, name):
    idx = _hash(name, len(buckets))
    return ll_find(buckets[idx], name)


def ht_delete(buckets, name):
    idx = _hash(name, len(buckets))
    buckets[idx] = ll_delete(buckets[idx], name)


def ht_list_all(buckets):
    entries = []
    for head in buckets:
        curr = head
        while curr is not None:
            entries.append((curr['name'], curr['phone']))
            curr = curr['next']
    entries.sort(key=lambda x: x[0])
    return entries

def bst_insert(root, name, phone):
    new_node = {'name': name, 'phone': phone, 'left': None, 'right': None}
    if root is None:
        return new_node

    parent = None
    curr = root
    while curr is not None:
        parent = curr
        if name < curr['name']:
            curr = curr['left']
        elif name > curr['name']:
            curr = curr['right']
        else:
            curr['phone'] = phone
            return root

    if name < parent['name']:
        parent['left'] = new_node
    else:
        parent['right'] = new_node
    return root


def bst_find(root, name):
    while root is not None:
        if name == root['name']:
            return root['phone']
        elif name < root['name']:
            root = root['left']
        else:
            root = root['right']
    return None


def _bst_min_node(node):
    while node and node['left'] is not None:
        node = node['left']
    return node


def bst_delete(root, name):
    if root is None:
        return None
    if name < root['name']:
        root['left'] = bst_delete(root['left'], name)
    elif name > root['name']:
        root['right'] = bst_delete(root['right'], name)
    else:
        if root['left'] is None:
            return root['right']
        if root['right'] is None:
            return root['left']
        min_node = _bst_min_node(root['right'])
        root['name'] = min_node['name']
        root['phone'] = min_node['phone']
        root['right'] = bst_delete(root['right'], min_node['name'])
    return root


def bst_list_all(root):
    def inorder(node, res):
        if node is None:
            return
        inorder(node['left'], res)
        res.append((node['name'], node['phone']))
        inorder(node['right'], res)
    result = []
    inorder(root, result)
    return result