Finding what scene number player is on and adding one....

I am making a level advancer script so I would use Application.LoadLevel (#) to load the next level. The problem is, how can I write a script to find which level number I'm on at the moment. Then to load the next level.

I'm guessing I would do something like this:

var nextLevel : int;
var win = false;

function Update () {

nextLevel = currentLevelNum + 1;

if (win = true) { Application.LoadLevel (nextLevel) }


The only problem would be finding what current level number the player is on. Is there a predefined thing for that?

Or would I need to set one up myself? If so, how?