import time
import random
import csv
import sys

# 1. LinkedList

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


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


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


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