public int bestInvitation2(String[] first, String[] second) {
		HashMap<String, Integer> map = new HashMap<String, Integer>();
		int max = 1;

		String[][] strings = new String[][] { first, second };
		for (String[] topics : strings) {
			for (String key : topics) {
				if (map.containsKey(key)) {
					int value = map.get(key) + 1;
					map.put(key, value);
					max = Math.max(value, max);
				} else {
					map.put(key, 1);
				}
			}
		}
		return max;
	}