<human>:  I have a question about optical character recognition, or OCR. What is the difference between OCR and OCR-A?
<bot>: OCR-A is a standard for optical character recognition. It is a subset of the OCR standard. OCR-A is a subset of OCR that is designed to be used in a specific application. For example, OCR-A is designed to be used in a specific type of document, such as a passport.