You are given a string `allowed` consisting of distinct characters and an array of strings `words`. A string is consistent if all characters in the string appear in the string `allowed`.

Return the number of consistent strings in the array `words`.

Example 1:

    Input: allowed = "ab", words = ["ad","bd","aaab","baa","badab"]
    Output: 2
    Explanation: Strings "aaab" and "baa" are consistent since they only contain characters 'a' and 'b'.

Example 2:

    Input: allowed = "abc", words = ["a","b","c","ab","ac","bc","abc"]
    Output: 7
    Explanation: All strings are consistent.

Example 3:

    Input: allowed = "cad", words = ["cc","acd","b","ba","bac","bad","ac","d"]
    Output: 4
    Explanation: Strings "cc", "acd", "ac", and "d" are consistent.

Constraints:

- `1 <= words.length <= 104`
- `1 <= allowed.length <= 26`
- `1 <= words[i].length <= 10`
- The characters in `allowed` are distinct.
- `words[i]` and `allowed` contain only lowercase English letters.