public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int t = in.nextInt();
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < t; i++) {
            builder.append("Case #").append(i + 1).append(": ");
            long n = in.nextLong();
            k = in.nextLong();
            y = z = 0;
            go(new Pair(1, n));
            builder.append(y).append(" ").append(z).append("\n");
        }
        System.out.println(builder);
    }
Why Did you create this class? what does it do?
src/codejam2018/Practice4.java