关于斐波那契数列的求和问题

public class Test {
    public static void main(String[] arg0){
        Scanner sc = null;
        while (true){
            sc = new Scanner(System.in);
            int month = sc.nextInt();
            System.out.println("兔子数为" + numOfRabbit(month) + "只");
        }
    }

    private static int numOfRabbit(int month) {
        if(month == 1 || month == 2)
            return 1;
        else return numOfRabbit(month - 1) + numOfRabbit(month - 2);
    }
}