Sahih Bukhari Volume 6, Book 61, Hadith Number 563.

Narrated By 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 used to recite, and they were eighteen Suras from the Mufassal, and two Suras from the Suras that start with Ha Mim.