What's the last yard of three yards?

The last code of the three codes is the health registration code. According to relevant public information, the last code of the three codes is the health registration code. Note: The three codes refer to health code, travel code and health registration code. Health codes are based on actual data and can be generated by citizens or people who have returned to work through online declaration and background audit. So the last code of the three codes is the health registration code.