Counting Strings

You are given a string s consisting of upper case Latin alphabets, i.e. from 'A' to 'Z'. Your task is to find how many strings t with length equal to that of S, also consisting of upper case Latin alphabet are there satisfying the following conditions: - String t is lexicographical larger than s - When you write both s and t in the reverse order, t is still lexicographical larger than s. Find o