Java 水仙数代码控制台无反应，问题出在哪？

public static boolean is(int a, int b, int c, int num) {
    return (a * a * a) + (b * b * b) + (c * c * c) == num;
}

public class c1t3 {
    public static Integer shuru() {
        Scanner reader = new Scanner(System.in);
        System.out.println("123");
        int date = reader.nextInt();
        return date;
    }

    public static void main(String[] args) {
        System.out.println("请输入一个三位数的整数");
        String a = shuru().toString();
        String[] b = a.split("");
        int[] math = new int[b.length];

        for (int i = 0; i < b.length; i++) {
            math[i] = Integer.parseInt(b[i]);
        }
        if (is(math[0], math[1], math[2], Integer.parseInt(a))) {
            System.out.println("这个数是水仙数");
        } else {
            System.out.println("这个不是水仙数");
        }
    }

    public static boolean is(int a, int b, int c, int num) {
        return (a * a * a) + (b * b * b) + (c * c * c) == num;
    }
}