From Sahih Bukhari (Hadith 5043):
Narrated Abu Wail:We went to `Abdullah in the morning and a man said, "Yesterday I recited all the Mufassal Suras." On that `Abdullah said, "That is very quick, and we have the (Prophet's) recitation, and I remember very well the recitation of those Suras which the Prophet (ﷺ) used to recite, and they were eighteen Suras from the Mufassal, and two Suras from the Suras that start with Ha Mim
Reference: Bukhari 5043