diff --git a/SpreadsheetsService/models/assignment.py b/SpreadsheetsService/models/assignment.py
index 4c686b3..3d09cb4 100644
--- a/SpreadsheetsService/models/assignment.py
+++ b/SpreadsheetsService/models/assignment.py
@@ -1,13 +1,20 @@
 from logging import addLevelName
+import uuid
 
 
 class Assignment(dict):
     """Задание."""
 
-    def __init__(self, name: str, points: list, weight: float = 1, 
-                subject: str = None, allow_to_display: bool = False,
-                how_to_display: str = 'z,1,1', 
-                notes: str = 'Замечаний по работе нет.'):
+    def __init__(
+        self,
+        name: str,
+        points: list,
+        weight: float = 1,
+        subject: str = None,
+        allow_to_display: bool = False,
+        how_to_display: str = "z,1,1",
+        notes: str = "Замечаний по работе нет.",
+    ):
         self.name = name
         self.subject = subject
         self.weight = weight
@@ -15,6 +22,7 @@ class Assignment(dict):
         self.allow_to_display = allow_to_display
         self.how_to_display = how_to_display
         self.notes = notes
+        self.uuid = uuid.uuid3(uuid.NAMESPACE_DNS, f"{name}{subject}")
         dict.__init__(
             self,
             name=self.name,
@@ -25,6 +33,7 @@ class Assignment(dict):
             allow_to_display=self.allow_to_display,
             how_to_display=self.how_to_display,
             notes=self.notes,
+            uuid=self.uuid,
         )
 
     @property
diff --git a/TelegramBot/bot.py b/TelegramBot/bot.py
index 16be060..ac23889 100644
--- a/TelegramBot/bot.py
+++ b/TelegramBot/bot.py
@@ -27,7 +27,7 @@ TOKEN = Path(".secrets/bot_token.txt").read_text()
 MESSAGES = Messages()
 HOST = "http://carolyn-spreadsheets:5000"
 BROADCAST_MESSAGE, BROADCAST_PUBLISH_DONE = range(2)
-GRADES_CALLBACK = 1
+GRADES_ASSNT, GRADES_VIEW = range(2)
 
 logging.setLoggerClass(TgLogger)
 logging.basicConfig(
@@ -77,118 +77,105 @@ def start(update: Update, context: CallbackContext):
     )
 
 
-def grades(update: Update, context: CallbackContext):
-    """Команда: Получить оценки студента."""
+def grades_start(update: Update, context: CallbackContext):
+    """Сообщение 'Выбери дисциплину'.
 
+    Обновляет текст сообщения и дает клавиатуру с выбором дисциплины.
+    """
     user_id = update.message.from_user.id
-
     start = time.monotonic()
     # Длинная операция, сообщим о запущенном процессе.
     look_msg = update.message.reply_html(MESSAGES.Assignments.START)
+
     try:
         data = requests.get(f"{HOST}/grades", params={"tg_id": user_id}).json()
-
-        subjects = data["subjects"]
-        assignments = data["assignments"]
-
-        if len(subjects) > 1:
-            context.user_data["subjects"] = subjects
-            context.user_data["all_assignments"] = assignments
-            reply_markup = build_menu_of_subjects(subjects)
-            msg = update.message.reply_text(
-                text=MESSAGES.Assignments.SELECT_COURSE, reply_markup=reply_markup
-            )
-        else:
-            context.user_data["assignments"] = assignments
-            reply_markup = build_menu_of_assignments(assignments)
-            msg = update.message.reply_text(
-                text=MESSAGES.Assignments.SELECT_ASSNT, reply_markup=reply_markup
-            )
-        
-        context.user_data["msg"] = msg
-        return_value = GRADES_CALLBACK
-
     except:
         LOG.exception("Failed to get grades.")
         update.message.reply_sticker(MESSAGES.Stickers.DEAD)
-        return_value = ConversationHandler.END
-    diff = time.monotonic() - start
-    look_msg.edit_text(MESSAGES.Assignments.timeit(diff))
-    return return_value
-
-
-def callback(update: Update, context: CallbackContext):
-
-    call = update.callback_query.data
-
-    # Нажатие кнопок при выборе задания
-    if call.startswith("assignment#"):
-
-        if "$back$" in call:
-            subjects = context.user_data["subjects"]
-            reply_markup = build_menu_of_subjects(subjects)
-            msg = update.callback_query.message.edit_text(
-                text=MESSAGES.Assignments.SELECT_COURSE, reply_markup=reply_markup
-            )
-            context.user_data["msg"] = msg
-            return GRADES_CALLBACK
-
-        assignments = context.user_data["assignments"]
-        name, subject = call.split("#")[1:3]
-
-        reply_markup = build_menu_of_assignments(
-            assignments, name, has_back_button=context.user_data["has_back_button"]
-        )
-
-        f = lambda ass: ass["name"] == name and ass["subject"] == subject
-        assignment = next(filter(f, assignments))
-        msg = update.callback_query.message.edit_text(
-            text=MESSAGES.Assignments.get(assignment['name'], 
-                                        assignment['points'],
-                                        assignment['how_to_display'],
-                                        assignment['notes']),
-            parse_mode=ParseMode.HTML,
-            reply_markup=reply_markup
-        )
-        context.user_data["msg"] = msg
-
-    # Нажатие кнопок при выборе дисциплины
-    if call.startswith("subject#"):
-        all_assignments = context.user_data["all_assignments"]
-        subject = call.split("#")[1]
-
-        f = lambda ass: ass["subject"] == subject
-        assignments = list(filter(f, all_assignments))
-        context.user_data["assignments"] = assignments
-        context.user_data["has_back_button"] = True
-
-        reply_markup = build_menu_of_assignments(assignments, has_back_button=True)
-        msg = update.callback_query.message.edit_text(
-            MESSAGES.Assignments.SELECT_ASSNT, reply_markup=reply_markup
-        )
-        context.user_data["msg"] = msg
-
-    if call.startswith("cancel#"):
-        update.callback_query.message.edit_text(
-            MESSAGES.Assignments.END,
-        )
         return ConversationHandler.END
 
-    return GRADES_CALLBACK
-
-def timeout(update: Update, context: CallbackContext):
-    msg = context.user_data["msg"]
-    msg.edit_text(
-        MESSAGES.Assignments.TIMEOUT, 
-        )
-    return ConversationHandler.END
-
-def grades_end(update: Update, context: CallbackContext):
-    msg = context.user_data["msg"]
-    msg.edit_text(
-        MESSAGES.Assignments.END
+    context.user_data["subjects"] = data["subjects"]
+    context.user_data["assignments"] = data["assignments"]
+    diff = time.monotonic() - start
+    look_msg.edit_text(MESSAGES.Assignments.timeit(diff))
+    update.message.reply_text(
+        MESSAGES.Assignments.SELECT_COURSE,
+        reply_markup=build_menu_of_subjects(data["subjects"]),
     )
-    return ConversationHandler.END
+    return GRADES_ASSNT
+
+
+def grades_pick_assignment(update: Update, context: CallbackContext):
+    """Сообщение 'Выбери задание'.
+
+    Обновляет текст сообщения и дает клавиатуру с выбором дисциплины.
+    В `callback_query` содержится имя предмета, либо ключевое слово.
+    Может завершить диалог.
+    """
+    query = update.callback_query
+    query.answer()
+    if query.data == "cancel":
+        query.edit_message_text(MESSAGES.Assignments.END, reply_markup=None)
+        return ConversationHandler.END
+    context.user_data["selected_subject"] = query.data
+    assignments = [
+        a for a in context.user_data["assignments"] if a["subject"] == query.data
+    ]
+    query.edit_message_text(
+        MESSAGES.Assignments.SELECT_ASSNT,
+        reply_markup=build_menu_of_assignments(assignments, has_back_button=True),
+    )
+    return GRADES_VIEW
+
+
+def grades_view(update: Update, context: CallbackContext):
+    """Отображение домашки.
+
+    В `callback_query` содержится UUID, идентификатор задания. Либо команда:
+    cancel или back. Может завершить диалог.
+    """
+    query = update.callback_query
+    query.answer()
+
+    if query.data == "cancel":
+        query.edit_message_text(MESSAGES.Assignments.END, reply_markup=None)
+        return ConversationHandler.END
+
+    if query.data == "back":
+        subjects = context.user_data["subjects"]
+        query.edit_message_text(
+            MESSAGES.Assignments.SELECT_COURSE,
+            reply_markup=build_menu_of_subjects(subjects),
+        )
+        return GRADES_ASSNT
+
+    assignments_map = {a["uuid"]: a for a in context.user_data["assignments"]}
+    assignment = assignments_map[query.data]
+    subject = context.user_data["selected_subject"]
+
+    raw_menu = build_menu(
+        [
+            InlineKeyboardButton("Отмена", callback_data="cancel"),
+            InlineKeyboardButton("⏮ Назад", callback_data=subject),
+        ],
+        2,
+    )
+
+    reply_markup = InlineKeyboardMarkup(raw_menu)
+
+    query.edit_message_text(
+        text=MESSAGES.Assignments.get(
+            assignment["name"],
+            assignment["points"],
+            assignment["how_to_display"],
+            assignment["notes"],
+        ),
+        parse_mode=ParseMode.HTML,
+        reply_markup=reply_markup,
+    )
+
+    return GRADES_ASSNT
+
 
 def broadcast(update: Update, context: CallbackContext):
     """Команда: разослать студентам."""
@@ -268,18 +255,12 @@ def main() -> None:
     start_handler = CommandHandler("start", start)
 
     grades_handler = ConversationHandler(
-        entry_points=[CommandHandler("grades", grades)],
+        entry_points=[CommandHandler("grades", grades_start)],
         states={
-            GRADES_CALLBACK: [CallbackQueryHandler(callback)],
-            ConversationHandler.TIMEOUT: [
-                MessageHandler(Filters.text | Filters.command, timeout)
-                ],
-            ConversationHandler.END: [
-                MessageHandler(Filters.text | Filters.command, grades_end)
-            ]
+            GRADES_ASSNT: [CallbackQueryHandler(grades_pick_assignment)],
+            GRADES_VIEW: [CallbackQueryHandler(grades_view)],
         },
         fallbacks=[CommandHandler("cancel", cancel)],
-        #conversation_timeout=10,
     )
 
     broadcast_handler = ConversationHandler(
@@ -294,7 +275,6 @@ def main() -> None:
     dispatcher.add_handler(start_handler)
     dispatcher.add_handler(grades_handler)
     dispatcher.add_handler(broadcast_handler)
-    #dispatcher.add_handler(callback_handler)
 
     # Начало работы бота
     updater.start_polling()
diff --git a/TelegramBot/messages/messages.py b/TelegramBot/messages/messages.py
index daaa16f..661383e 100644
--- a/TelegramBot/messages/messages.py
+++ b/TelegramBot/messages/messages.py
@@ -30,20 +30,24 @@ class Messages:
 
         @staticmethod
         def get(name: str, assignment: list, how_to_display: str, notes: str):
-            is_float, n_cols, n_rows = how_to_display.split(',')
+            is_float, n_cols, n_rows = how_to_display.split(",")
             n_cols, n_rows = int(n_cols), int(n_rows)
-            summary = f'<b>{name}</b>:\n'
-            if is_float == 'z':
-                d = {0 : '❎', 1 : '✅'}
+            summary = f"<b>{name}</b>:\n"
+            if is_float == "z":
+                d = {0: "🟥", 1: "✅"}
                 for item in range(0, len(assignment), n_cols):
-                    summary += ''.join(list(map(d.get, 
-                        assignment[item : item + n_cols]))) + '\n'
-            elif is_float == 'r':
-                to_str = lambda x: f'{x:.2f}'
+                    summary += (
+                        "".join(list(map(d.get, assignment[item : item + n_cols])))
+                        + "\n"
+                    )
+            elif is_float == "r":
+                to_str = lambda x: f"{x:.2f}"
                 for item in range(0, len(assignment), n_cols):
-                    summary += ' '.join(list(map(to_str,
-                        assignment[item: item + n_cols]))) + '\n'
-                summary += f'Σ: {to_str(sum(assignment))}\n'
+                    summary += (
+                        " ".join(list(map(to_str, assignment[item : item + n_cols])))
+                        + "\n"
+                    )
+                summary += f"Σ: {to_str(sum(assignment))}\n"
             summary += f"\n{notes}"
             return summary
 
diff --git a/TelegramBot/utils/inline_keyboard.py b/TelegramBot/utils/inline_keyboard.py
index b443c0c..fc3cd30 100644
--- a/TelegramBot/utils/inline_keyboard.py
+++ b/TelegramBot/utils/inline_keyboard.py
@@ -5,41 +5,36 @@ from telegram import (
 
 
 def build_menu_of_subjects(subjects: list) -> InlineKeyboardMarkup:
-    button_list = []
-    for subject in subjects:
-        button_list.append(
-            InlineKeyboardButton(subject, callback_data=f"subject#{subject}")
-        )
-    end_button = [InlineKeyboardButton("Отмена", callback_data="cancel#")]
-    return InlineKeyboardMarkup(build_menu(button_list, n_cols=2, 
-                                        footer_buttons=end_button))
+    button_list = [
+        InlineKeyboardButton(subject, callback_data=subject) for subject in subjects
+    ]
+    end_button = [InlineKeyboardButton("Отмена", callback_data="cancel")]
+    return InlineKeyboardMarkup(
+        build_menu(button_list, n_cols=2, footer_buttons=end_button)
+    )
 
 
 def build_menu_of_assignments(
-    assignments: dict, pressed_name: str = None, has_back_button: bool = False
+    assignments: dict, has_back_button: bool = False
 ) -> InlineKeyboardMarkup:
     button_list = []
     for assignment in assignments:
-        if not assignment['allow_to_display']:
+        if not assignment["allow_to_display"]:
             continue
-        if pressed_name and assignment["name"] == pressed_name:
-            title = f'💁‍♀️ {assignment["name"]}'
         else:
             title = assignment["name"]
         button_list.append(
             InlineKeyboardButton(
                 title,
-                callback_data=f'assignment#{assignment["name"]}'
-                + f'#{assignment["subject"]}',
+                callback_data=assignment["uuid"],
             )
         )
     if has_back_button:
-        button_list.append(
-            InlineKeyboardButton("Назад", callback_data=f"assignment#$back$")
-        )
-    end_button = [InlineKeyboardButton("Отмена", callback_data="cancel#")]
-    return InlineKeyboardMarkup(build_menu(button_list, n_cols=3, 
-                                        footer_buttons=end_button))
+        button_list.append(InlineKeyboardButton("⏮ Назад", callback_data="back"))
+    end_button = [InlineKeyboardButton("Отмена", callback_data="cancel")]
+    return InlineKeyboardMarkup(
+        build_menu(button_list, n_cols=3, footer_buttons=end_button)
+    )
 
 
 def build_menu(buttons, n_cols, header_buttons=None, footer_buttons=None):