Java script help

I am making a Script that counts down time

My code is:

var DecayTime : int = 1;
var CurrentTime : int = 300;
var MaxTime : int = 300;

function Awake () {
CurrentTime = MaxTime;

}

function Update() {

 guiText.text = "" + CurrentTime;
 
}
function FixedUpdate() {
CurrentTime -= DecayTime == CurrentTime;
}

The compiler is giving me :

Assets/Scripts/count_Death.js(16,13): BCE0051: Operator ‘-’ cannot be used with a left hand side of type ‘int’ and a right hand side of type ‘boolean’.

I am new with unityscript but please be straight with me

Line 16 you have a == when you want only =.

== is a comparison operator and the statement will return true/false aka boolean value.

What are you trying to do with Line 16 anyway (seems weird)?