In which category of madd the letter noon (in surah al qalam) would be considered?

Question
 In which category of madd the letter نون (in surah al qalam) would  be considered?
Answer
The separate letter نون at the beginning of surah Al-Qalam is مد لازم حرفي مخفف because the last نون doesn't merge into the next letter for Hafs 'an 'Aasim by the way of Ash-Shaatibiyyah.