public static long max(long first, long... rest) {
        long max = first;
        for (long r : rest) {
            if (r > max)
                max = r;
        }
        return max;
    }
@Test
    public void testMax() {
        assertEquals(1, Utils.max(1));
        assertEquals(3, Utils.max(1, 2, 3));
        assertEquals(3, Utils.max(2, 1, 3, 3));
        assertEquals(100, Utils.max(0, 2, 2, 100));
        assertEquals(-1, Utils.max(-1, -2, -2, -10, -100, -1000));
        assertEquals(0, Utils.max(-1, -2, -2, -10, -150, -1800, 0));
    }