title: Django ORM specifc query
body: <p>I have 2 django models:</p>
  
  <pre><code>class TelegramUser(models.Model):
      telegram_id = models.IntegerField()
      telegram_username = models.TextField(max_length=255, default=None, blank=True, null=True)
      first_name = models.TextField(max_length=255, default=None, blank=True, null=True)
      last_name = models.TextField(max_length=255, default=None, blank=True, null=True)
      has_blocked = models.BooleanField(default=False)
  </code></pre>
  
  <pre><code>class DutyDate(models.Model):
      date = models.DateField(default=None, blank=True, null=True)
      telegram_user = models.ForeignKey(TelegramUser, on_delete=models.SET_NULL, null=True)
      group = models.ForeignKey(UserGroup, on_delete=models.CASCADE, null=True)
      mark = models.FloatField(max_length=255, default=0)
      is_open = models.BooleanField(default=True)
  </code></pre>
  
  <p>I need to get all users, who has less than 3 assigned DutyDates. Can I do it with one query and how?</p>