public void insert(String item) {
		// make case-insensitive
		item = item.toLowerCase();
		Integer count = 0;
		for (int i = 0; i < item.length(); i++) {
			Character c = item.charAt(i);

			// get ASCII value for current char
			int charIndex = (int) c;

			count = map.get(charIndex);
			count = count + 1;

			map.set(charIndex, count);
		}
	}