Given an array of strings `words`, return the words that can be typed using letters of the alphabet on only one row of American keyboard like the image below.

In the American keyboard:

- the first row consists of the characters `"qwertyuiop"`,
- the second row consists of the characters `"asdfghjkl"`, and
- the third row consists of the characters `"zxcvbnm"`.

Example 1:

    Input: words = ["Hello","Alaska","Dad","Peace"]
    Output: ["Alaska","Dad"]

Example 2:

    Input: words = ["omk"]
    Output: []

Example 3:

    Input: words = ["adsdf","sfd"]
    Output: ["adsdf","sfd"]

Constraints:

- `1 <= words.length <= 20`
- `1 <= words[i].length <= 100`
- `words[i]` consists of English letters (both lowercase and uppercase).