Count of CheckBoxList items selected isn't being calculated correctly

I'm currently trying to get a count of a CheckBoxList to use in conjunction with an if and else statement for a project. If the count is not equal to 2 I have a label that prompts the user to select two modules but the count isn't being calculated properly. Any help would be appreciated. Here is the code in question:

protected void RegisterButton_Click(object sender, EventArgs e) {

    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["UniString"].ConnectionString);
    //This integer will hold the number of modules selected
    Int32 amount = 0;

    for (int i = 0; i < CheckBoxList1.Items.Count; i++)
    {
        //amount will increment each time a module checkbox is checked
        if (CheckBoxList1.Items[i].Selected)
        {
            amount = amount++;

        }

        //If amount is not equal to 2 the code below will run
        if (amount != 2)
        {
        //If the number of modules selected is not equal to 2 then this message is displayed and the background of the label in the markup is turned red to draw attention

            ModuleSelectionMessage.Text = "Please select 2 modules to successfully register";
            ModuleSelectionMessage.BackColor = System.Drawing.Color.Red;

        }
        else
        {...