class Company extends Model
{
    public function departments()
    {
        return $this->hasMany('App\Department');
    }

    public function results()
    {
        return $this->hasMany('App\Result');
    }
}

class Department extends Model
{
    public function cities()
    {
        return $this->belongsToMany('App\City');
    }

    public function company()
    {
        return $this->belongsTo('App\Company');
    }
}

class City extends Model
{
    public function departments()
    {
        return $this->belongsToMany('App\Department');
    }
}

class Result extends Model
{
    public function company()
    {
        return $this->belongsTo('App\Company');
    }

    public function city()
    {
        return $this->belongsTo('App\City');
    }

}