Two strings `word1` and `word2` are considered almost equivalent if the differences between the frequencies of each letter from `'a'` to `'z'` between `word1` and `word2` is at most `3`.

Given two strings `word1` and `word2`, each of length `n`, return `true` if `word1` and `word2` are almost equivalent, or `false` otherwise.

The frequency of a letter `x` is the number of times it occurs in the string.

Example 1:

    Input: word1 = "aaaa", word2 = "bccb"
    Output: false
    Explanation: There are 4 'a's in "aaaa" but 0 'a's in "bccb".
    The difference is 4, which is more than the allowed 3.

Example 2:

    Input: word1 = "abcdeef", word2 = "abaaacc"
    Output: true
    Explanation: The differences between the frequencies of each letter in word1 and word2 are at most 3:
    - 'a' appears 1 time in word1 and 4 times in word2. The difference is 3.
    - 'b' appears 1 time in word1 and 1 time in word2. The difference is 0.
    - 'c' appears 1 time in word1 and 2 times in word2. The difference is 1.
    - 'd' appears 1 time in word1 and 0 times in word2. The difference is 1.
    - 'e' appears 2 times in word1 and 0 times in word2. The difference is 2.
    - 'f' appears 1 time in word1 and 0 times in word2. The difference is 1.

Example 3:

    Input: word1 = "cccddabba", word2 = "babababab"
    Output: true
    Explanation: The differences between the frequencies of each letter in word1 and word2 are at most 3:
    - 'a' appears 2 times in word1 and 4 times in word2. The difference is 2.
    - 'b' appears 2 times in word1 and 5 times in word2. The difference is 3.
    - 'c' appears 3 times in word1 and 0 times in word2. The difference is 3.
    - 'd' appears 2 times in word1 and 0 times in word2. The difference is 2.

Constraints:

- `n == word1.length == word2.length`
- `1 <= n <= 100`
- `word1` and `word2` consist only of lowercase English letters.