class mk_link_student(models.Model):
    _name = 'mk.link.student'
    _description = 'Link Student With Stage'
    _rec_name = 'name_stage_id'

    name_stage_id = fields.Many2one(
        'mk.stage',string='Name Stage',
    )

    remain_num = fields.Integer(
        string='Remaining number',
        compute='total_student'
       
student_ids = fields.Many2many('mk.student.register', string = 'Student')

i want compute field in remain_number depend on student_ids field many2many

@api.one
    @api.depends('student_ids')
    def total_student(self):
        max_n = self.name_stage_id.max_number
        for rec in self:
            student = rec.student_ids.ids
            if student:
                result = max_n - student

and give me this Error:

result = max_n - student TypeError: unsupported operand type(s) for -: 'int' and 'list'