The alphabet of which the letter Sad is a part includes how many letters?
Sad (surah):  Sad (ص) is the name of the eighteenth letter in the Arabic alphabet. Arabic alphabet: The Arabic alphabet (Arabic: الأَبْجَدِيَّة العَرَبِيَّة‎ ‎ "al-abjadīyah al-ʻarabīyah ", or الحُرُوف العَرَبِيَّة "al-ḥurūf al-ʻarabīyah ") or Arabic abjad is the Arabic script as it is codified for writing the Arabic language.
i don't know