Write string and long extension methods that convert between Roman and Arabic numerals. Use the usual Roman digits, I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, and M = 1,000. Also use the usual rules so that digits add unless a digit precedes a larger digit. For example, IX means subtract I from X to get 10 – 1 = 9.

Finally, support one extra rule that the Romans sometimes used to represent large numbers. That rule uses parentheses to represent multiplication by 1,000. For example, (IV)XIV means 4,014. Parentheses can be nested, as in ((XX)III)IV for 20,003,004, but won't appear in two places not nested, as in ((X))(III)IV.