private static Integer getInt() {
		Boolean flag;
		int numInt = 0;
		do {
			Scanner scanner = new Scanner(System.in);
			try {
				numInt = scanner.nextInt();
				flag = true;
			} catch (Exception e) {
				flag = false;
				System.out.println("Input type mismatch!");
				System.out.print("Please input in Integer: ");
			}
		} while (!flag);
		return numInt;
	}