Third digit

     N	R	    N	R
 			     (IVXLCDM)

  1	I	  100	C
  2	II	  200	CC
  3	III	  300	CCC
  4	IV	  400	CD
  5	V	  500	D
  6	VI	  600	DC
  7	VII	  700	DCC
  8	VIII	  800	DCCC
  9	IX	  900	CM