Timer count down

Hey everyone. So I want to set up a time trial for my game. Players try to score points while the counter starts counting down. Now I have a script to keep track of time.

static var strTime : String;
static var timeCount : float = 0.0;
var intSec : int = 0;
var intMin : int = 0;
var strSecZeroFill : String;
var strMinZeroFill : String;

function FixedUpdate(){

strSecZeroFill = “”;
strMinZeroFill = “”;
timeCount += Time.deltaTime;
intSec = Mathf.FloorToInt(timeCount)%60;
intMin = timeCount/60;

if(intSec < 10){
strSecZeroFill = “0”;
}

if(intMin < 10){
strMinZeroFill = “0”;
}

strTime = strMinZeroFill + intMin + “min” + strSecZeroFill + intSec + “sec”;

print(strTime);

}

How would I set it up to count down though? Any help as always is greatly appreciated!

Try this video.