Input Variable always gets NaN

Hey, I´ve been looking for this particular problem everywhere and can´t find a solution.
I have 2 input text boxes and a button. this is the code:

//in a frame

var alto_in:Number = 0;
var ancho_in:Number = 0;

var total:Number = 0;

//in the button

on (release) {

ancho = (Number(ancho_in)+Number(alto_in)+);


thanx in advance