Find a mapping Mchar> so that

if we change all the letters in the strings equals to M[c] into c,

the strings will be in lexicographical order.

For instance,let's look at the first sample test

M is like this:

abcdefghijklmnopqrstuvwxyz

bcdefghijklmnopqrsatuvwxyz

so "rivest" will become "qhvfrt","shamir" will become "rgslhq",etc.

and you'll find all the words in lexicographical order

your task is to find any of these mappings

In the Question you are provided with a list of strings that are said to be in lexicographical order. Now you need to find any order (permutation) of the 26 letters of the English alphabet which satisfies the fact that the given list is in lexicographical order.