public String convertToTitle(int n) {

		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			int r = n % 26;
			if (r == 0) {
				n = n - 26;
				r = 25;
			} else {
				r = r - 1;
			}
			n = n / 26;
			sb.insert(0, (char) ('A' + r));

		}
		return sb.toString();
	}