Django did not working about 'TemplateDoesNotExist at /polls/3/'

I want make a django’s tutoreal, vote site, but I can’t show those site page work.

Exception Type: TemplateDoesNotExist
Exception Value: polls/detail.html

detail.html

<form action="{% url 'polls:vote' question.id %}" method="post">
  {% csrf_token %}
  <fieldset>
    <legend>
      <h1>{{ question.question_text }}</h1>
    </legend>
    {% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}
    {% for choice in question.choice_set.all %}
    <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}">
    <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br>
    {% endfor %}
  </fieldset>
  <input type="submit" value="Vote">
</form>

index.html

{% if lastest_question_list %}
  <ui>
    {% for question in lastest_question_list %}
      <li><a href="{% url 'polls:detail' question.id %}">{{ question.question_text }}</a></li>
    {% endfor %}
  </ui>
{% else %} 
  <p>No polls are available.</p>
{% endif %}

result.html

<h1>{{ question.question_text }}</h1>

<ul>
  {% for choice in question.choice_set.all %}
  <li>{{ choice.choice_text }} -- {{ choice.votes }} vote{{ choice.votes|pluralize }}</li>
  {% endfor %}
</ul>

<a href="{% url 'polls:detail' question.id %}">Vote again?</a>

urls.py

from django.urls import path

from . import views

app_name = 'polls'
urlpatterns = [
    path('', views.IndexView.as_view(), name='index'),
    path('<int:pk>/', views.DetailView.as_view(), name='detail'),
    path('<int:pk>/results/', views.ResultsView.as_view(), name='results'),
    path('<int:question_id>/vote/', views.vote, name='vote'),
]

I wish I helped. thank you.

Thank you for watching.
I have done this problem about file’s name result.html → results.html