private static int parseNumber(String str) {
		try {
			return Integer.parseInt(str);
		} catch (NumberFormatException e) {
			if (str.matches("one")) {
				return 1;
			} else if (str.matches("two")) {
				return 2;
			} else if (str.matches("three")) {
				return 3;
			} else if (str.matches("four")) {
				return 4;
			} else if (str.matches("five")) {
				return 5;
			} else if (str.matches("sixe?")) {
				return 6;
			} else {
				throw new IllegalArgumentException("Could not parse number.", e);
			}
		}
	}