A 21-year-old woman came to a surgeon 5 hours after she had scalded her left forearm with boiling water. Objectively, a skin patch 17x10 cm in size had flaccid vesicles; epidermis there was torn and displaced in some areas. The wound bottom was whitish-gray, dry, and its pain sensitivity was reduced. After a treatment with bandages soaked with a solution of furacilin (nitrofural), levosin, and hiposol, on the 29th day after the burn, the necrotic scab came off, leaving a pink superficial scar in its place. What was the degree of the burn in this case?