public String convertToTitle(int n) {
		String result = "";
		Stack<Character> stack = new Stack<Character>();
		while (n != 0) {
			int num = (n - 1) % 26;
			stack.push((char) ('A' + num));
			n = (n - 1) / 26;
		}
		while (!stack.isEmpty()) {
			result += stack.pop();
		}
		return result;
	}