Limit the amount of checkboxes selected on Adobe Acrobat using Javascript?

Hi, I am trying to limit the amount of checkboxes that someone can someone can select on a form i created using Adobe Acrobat Pro DC. Below is the javascript that I am using, however I repeatedly keep getting this error message Syntax Error: missing formal parameter 1: at line 2. Can anyone assist?

Thanks

function limitCheckNumber("check", 0, 26, 3) {

   // Initialize the selected check box count

    var count = ;

    // Loop through the check boxes to see if the limit has been exceeded

    for (var i = lower; i < upper + 1; i += 1) {

        // Increment the counter if the current check box is selected

        if (getField(prefix + "." + i).value !== "Off") count += 1;

        // If the count exceeds the limit, deselect the check box that was just selected

        // and alert the user

        if (count > max) {

            event.target.value = "Off";

            app.alert("A maximum of " + max + " check boxes can be selected", 3);

            break;

        }

    }

}