There is a new alien language that uses the English alphabet. However, the order among the letters is unknown to you. You are given a list of strings `words` from the alien language's dictionary, where the strings in `words` are **sorted lexicographically** by the rules of this new language. Derive the order of letters in this language, and return *it as a string* `order`. If there is no solution, return `""`. If there are multiple solutions, return *any one of them*. For grading purposes on this platform, the chosen test cases each have a unique valid ordering.