Any computer programming language or software package that is used to compute "D" mod "97" directly must have the ability to handle integers of more than 30 digits. In practice, this can only be done by software that either supports arbitrary-precision arithmetic or that can handle 220 bit (unsigned) integers, features that are often not standard. If the application software in use does not provide the ability to handle integers of this size, the modulo operation can be performed in a piece-wise manner (as is the case with the UN CEFACT TBG5 Javascript program).