static boolean isOverLimit(long a, long b) {
    return Math.multiplyExact(a, b) >= 250_000;
  }
@Test
  public void isOverLimit() {
    assertThat(BlockRecognizer.isOverLimit(20, 40)).isFalse();
    assertThat(BlockRecognizer.isOverLimit(3, 100_000)).isTrue();

    // multiplication of these two ints is higher than Integer.MAX_VALUE
    assertThat(BlockRecognizer.isOverLimit(50_000, 60_000)).isTrue();
  }