Staying true to its word, Walgreens Boots Alliance will shutter 600 stores across the U.S. starting next year.

The majority of the closures will be Rite Aid locations but may include some Walgreens stores if it is within a mile of another Walgreens or Rite Aid site, Crain’s Chicago Business reports.

Any remaining Rite Aid stores will be rebranded to Walgreens over the next few years. Walgreens is spending $750M on the rebrand along with another $500M to convert existing Rite Aid stores.

After several delays, Walgreens received regulatory approval in September to purchase 1,932 Rite Aid stores, three distribution centers and existing inventory for $4.38B. The original deal experienced heavy scrutiny from the Federal Trade Commission regarding antitrust concerns before being abandoned by both companies.

It is estimated that the store shuttering process will take 18 months to complete and will cost $450M, though Walgreens estimates the cost savings will yield approximately $300M annually by the end of 2020.

The process is set to begin by spring 2018.