Unexpected token?

I have this script and Unity is telling me that 'timerscript is an unexpected token'

And I just can't figure out what's wrong with it

 var timerscript : timerscript;
 var AddAmmo = 1;
 
 function OnTriggerEnter()
 
 timerscript = gameObject.Find("Night Camera").getComponent("CamTimer");
 
 if (AddAmmo <= 0){
 timerscript.timer += 20.0;
 AddAmmo -= 1;
 }