public String getSession(int i){
		String hr, min;
		try{
			hr = Integer.toString(session[i].get(11));
			if (hr.length()==1)
				hr = "0" + hr;
			min = Integer.toString(session[i].get(12));
			if (min.length()==1)
				min = "0" + min;
			return hr + ":" + min;
		} catch(NullPointerException e){
		}
		return null;
	}