Obtain the number of students of a teacher

• teacher has a one-to-many relationship with the course.

• course belongs to one teacher.

• student can participate in several courses.

• course can include several students.

According to Laravel standards, I also wrote the interface and relation table in the model.

Now I want to get the number of students of a teacher in TeachersController And if possible, get a list of his students.

Teacher Model

public function course()
{
    return $this->hasMany(course::class);
}

Course Model

public function teacher()
{
    return $this->belongsTo(Teacher::class);
}

public function students()
{
    return $this->belongsToMany(Student::class)
        ->withPivot('start_date', 'cancel_date', 'status');
}

Student Model

public function courses()
{
    return $this->belongsToMany(course::class)
        ->withPivot('status', 'start_date', 'cancel_date');
}

I tried to get the list and number of students through the course model defined in the teacher relation to the student model defined in the course model. But Laravel makes a mistake.

public function show(Teacher $teacher)
{
    $countStudent =  $teacher->course()->get()->students();
    dd($countStudent);
}

You can use hasManyThrough relationship here

Teacher.php

 public function students() {
    return $this->hasManyThrough(Student::class, Course::class);
 }

in your controller

public function show(Teacher $teacher){

 $countStudent =  $teacher->students()->count();
    dd($countStudent);

}