You wrote this: def add(c1, c2): ord(c1) - ord('a') + 1 ord(c2) - ord('a') + 1
First of all, this looks like homework. People will help you with concepts here, but most frown on just providing answers. With that in mind look at this: >>> ord('A') 65 >>> ord('a') 97 >>> In your assignment you refer to Upper case letters. In your code you take the ordinal value of lower case 'a' -- Joel Goldstick http://joelgoldstick.com -- https://mail.python.org/mailman/listinfo/python-list