Late Roman Bronze Coins

Hello gentlemen,
I bought a batch of Roman coins, my idea is to learn how to identify the most common types.
To my surprise, some of them weren't extremely common.
In the batch there was also a Campgate (I had none so I was glad) but even more, from Constantine II and I know campgates are not extremely common for him.

What I would like to confirm with you please is the full mintmark - SMH (...)
Obverse is CONSTANTINVS IVN NOB C
I am pretty sure this is RIC VII Heraclea 107 - campgate, eight layers, two turrets, star above, no door. Star in left field  - but I cannot distinguish the last character in the exergue.

Based on the picture it would be either A or delta. I would lean towards A.

Thank you.