Walgreens plans to close about 600 drugstores as it completes a $4.38 billion deal to buy nearly 2,000 stores from rival Rite Aid.

Company spokesman Michael Polzin said Wednesday that most of the closings will be Rite Aid stores, and the vast majority will be within a mile of another store in the Walgreens network.

Walgreens isn’t saying which stores will close.

The store closings will start next spring and be completed over 18 months. Walgreens operates more than 13,200 stores worldwide.