Subanagrams

Let's start from some definitions. Strings A and B are called anagrams if it's possible to rearrange the letters of string A using all the original letters exactly once and achieve string B; in other words A and B are permutations of each other. For example, remote and meteor are anagrams, race and race are anagrams as well, while seat and tease aren't anagrams as tease contains an extra 'e'. St