Memory system

A memory system comprising:

• a non-volatile memory including a first memory region, a second memory region, a third memory region, and a fourth memory region, each of the first memory region, the second memory region, the third memory region, and the fourth memory region including a plurality of memory cells;
• and
• a controller configured to:
• perform a first processing including calculating a first voltage corresponding to the first memory region;
• perform a second processing after the first processing, the second processing including calculating a second voltage corresponding to the third memory region;
• after the first processing and before the second processing, use the first voltage when reading data from the first memory region and use a third voltage calculated based on the first voltage when reading data from each of the second memory region, the third memory region, and the fourth memory region;
• and
• after the second processing, use the first voltage when reading data from the first memory region, use a fourth voltage calculated based on the second voltage when reading data from each of the second memory region and the fourth memory region, and use the second voltage when reading data from the third memory region.