You are to assign each of 39,000,000 individuals with a distinct (unique) k-character pattern involving the digits (\\\'0\\\' through \\\'9\\\'), uppercase letters (\\\'A\\\'through \\\'Z\\\') and the underscore character (\\\'_\\\'), with the provision that the first (leftmost) of the k-character must be one of the uppercase letters (\\\'A\\\' through \\\'Z\\\'). What is the minimum k that you will need?