numberRemoved = oldCount;
      backingMap.remove(element);
    }

    frequency.add(-numberRemoved);
    size -= numberRemoved;
    return oldCount;
  }

  // Roughly a 33% performance improvement over AbstractMultiset.setCount().
  @CanIgnoreReturnValue
  @Override
  public int setCount(@ParametricNullness E element, int count) {
    checkNonnegative(count, "count");

    Count existingCounter;

        continue;
      }
      int alphaIndex = getAlphaIndex(c1);
      // This was also benchmarked using '&' to avoid branching (but always evaluate the rhs),
      // however this showed no obvious improvement.
      if (alphaIndex < 26 && alphaIndex == getAlphaIndex(c2)) {
        continue;
      }
      return false;
    }
    return true;
  }

  /**

        continue;
      }
      int alphaIndex = getAlphaIndex(c1);
      // This was also benchmarked using '&' to avoid branching (but always evaluate the rhs),
      // however this showed no obvious improvement.
      if (alphaIndex < 26 && alphaIndex == getAlphaIndex(c2)) {
        continue;
      }
      return false;
    }
    return true;
  }

  /**

   * to prove its primality. Values from miller-rabin.appspot.com.
   *
   * NOTE: We could get slightly better bases that would be treated as unsigned, but benchmarks
   * showed negligible performance improvements.
   */
  private static final long[][] millerRabinBaseSets = {
    {291830, 126401071349994536L},
    {885594168, 725270293939359937L, 3569819667048198375L},