I have an 1864 $50.00 confederate bill. No.5845 on the front with Richmond, Feb, 17th. The back of the bill is all green with a fine type of tiny pattern in the background with huge letters FlFTY right in the center of the bill, with a large 50 in each of the 4 corners. I know it is a real bill because I know my grandfather gave it to my dad who gave it to me. Do you know how much if anything it is worth?