Two strings x and y are considered similar if they are either exactly the same or can be made identical by swapping at most two different characters in string x.

We define a similarity group as a set of strings where each string is similar to at least one other string in the group. A string doesn't need to be directly similar to every other string in the group — it just needs to be connected to them through a chain of similarities.

Given a list of strings strs, where each string is an anagram of the others, your task is to determine how many such similarity groups exist in the list.

Constraints:

• $1 \leq$ strs.length $\leq 300$

• $1 \leq$ strs[i].length $\leq 300$

• strs[i] consists of lowercase letters only.

• All words in strs have the same length and are anagrams of each other.