Roman coin Constantine (?) [επιλυμένο]

Hello, I need help with this coin since there are many Emperors called Constantine or Constantius. I can't seem to find who is on this coin.

Thank you.

N#208151 

 Your one joined picture in PNG I changed to two JPEG … 

 then put those in the Search and that was the first result. 

CONSTANTINVS IVN NOB C // GLOR - IA EXERC - ITVS 

 Comparison, and some lettering added: 

Thank you kindly, sadly I still don't have such a sharp eye for roman coins.

So, it is the same coin but variation is different? 

 Similar. How is it different? 

You gave no size; is yours 18mm like that? 

 I just put your separated pictures in the Search: 

https://en.numista.com/catalogue/index.php?r=&ct=coin&im1=62f949717a228.jpg&im2=62f94976de4b3.jpg&tb=y&tc=y&tn=y&tp=y&tt=y&cat=y&ru=&ca=3&no=&v=&i=&b=&d=&u=&a=&dg=&m=&f=&t=&w=&mt=&g=&se=&c=&wi=&sw= 

 I know nothing about ancient coins.