Spam check in Flash Form AS 2

1

I have a simple mail form with One Name Input field, one Email Input Field,
one Message Input Field. Now I have another Static Text and before this Text
I write two number "35 " and an Input Field with the caption “Put This Number Before Posting” . If the user do not put this number ( 35) he will be restricted to post , he only allowed to post when he put this particular number ( 35) in this Input field.
How can I do this?

Below is the code I am using for the other three
fields. Shall be glad if any one help me.

sender.onRelease = function() {
    if (theName.text == "") {
        errortxt1.text = "Enter your name ";
    } else if (theEmail.text.indexOf("@") == -1) {
        errortxt1.text = "Enter An Email";
    } else if (theMessage.text == "") {
        errortxt1.text = " Your Message Please ";
    } else {
        errortxt1.text = "";
        senderLoad.theName = theName.text;
        senderLoad.theEmail = theEmail.text;
        senderLoad.theMessage = theMessage.text;
        senderLoad.sendAndLoad("mail.php", receiveLoad);
        gotoAndStop("wait");
    }
};