Help to identify this old coin

Hello,

This is a roman provincial coin of Moesia, Viminiacum.
I'm not sure about the obverse legends. Looking at the bust I would have said Traianus Decius but I'm not sure. Which letters do you read ?

On reverse there is the date : AN XII. Only a few emperors have that date so it facilitates the search.

See here :
http://www.wildwinds.com/coins/greece/moesia/viminacium/i.html

thanks for help me.

It's difficult to read because the coin is damage

Weight about 8,5g
Medal alignment

This may be from:
Trebonianus Gallus 251-254 AD
Viminacium, Moesia Superior

o. IMP C GALLVS P FELIX AVG
laureate, draped and cuirassed bust of Gallus r.
r. P M S COL VIM
Moesia standing l.; at l., bull standing r.; at r., lion standing l.
ex: AN XIV
Roman Provincial Coinage v. IX p66 #83. Around 9.4 g, 25-28 mm.
The bull and lion are emblems of legions VII and IV, which were quartered in the province.