private String setTime(long ms){
		if(TimeUnit.MILLISECONDS.toMinutes(ms) >= 40)
			return String.format("%02d:%02d", 
			    (TimeUnit.MILLISECONDS.toMinutes(ms) - 40) ,
			    TimeUnit.MILLISECONDS.toSeconds(ms) - 
			    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(ms)));
		else if(TimeUnit.MILLISECONDS.toMinutes(ms) >= 20)
			return String.format("%02d:%02d", 
				    (TimeUnit.MILLISECONDS.toMinutes(ms) - 20) ,
				    TimeUnit.MILLISECONDS.toSeconds(ms) - 
				    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(ms)));
		else
			return String.format("%02d:%02d", 
				    TimeUnit.MILLISECONDS.toMinutes(ms) ,
				    TimeUnit.MILLISECONDS.toSeconds(ms) - 
				    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(ms)));
	}