I assume the medals must be hanging from a string or a rope such that they can be 'flipped' easily. Such is not stated, but is logical, and would mean that the 50th soldier could know on his first trip that he is the 50th soldier to be summoned because more information can be stored and conveyed...
evan in 800 BC soldiers have bin given pay for their work with the army m8 unless of course you are talking about slave fighters but these are soldiers so thus they are getting money look at today and now they pay soldiers as they have for a very long time
this is not a mathematical qeustion it is a logistics case if he can call the same soldier in as many times as he wants he could keep this going on for eternity and they cannot talk to each other about who was called so the general could leave one soldier out the whole time and maybe call him...