public long RamBytesUsed(){return RamUsageEstimator.AlignObjectSize(3 * RamUsageEstimator.NUM_BYTES_OBJECT_REF + 2 * RamUsageEstimator.NUM_BYTES_INT32)+ RamUsageEstimator.SizeOf(data)+ positions.RamBytesUsed()+ wordNums.RamBytesUsed();}