 *** You may only submit a given problem once  no resubmissions will be accepted. ***
A nozero number system uses only the digits 1 through 9. So counting begins with 1, the first
"counting number", and continues:

1,2,3,4,5,6,7,8,9,11,12,...,19,21,...,98,99,111,112,...
So, in this system 9 is the ninth counting number and 11 is the tenth counting number.
As usual, addition can be defined by reference to the counting sequence. Addition of the ith counting number and the jth counting number is defined to mean the (i+j)th counting number. Thus, in this system
5 + 8 = 14, since 5 is the fifth counting number, 8 is the eighth, and 14 is the thirteenth counting number. Subtraction
is the reverse of addition. Create a class NoZero that contains the method subtract that
takes two nozero numbers, big and small, and returns the nozero value that results
from calculating big  small.
