给你一个由不同字符组成的字符串 allowed 和一个字符串数组 words 。如果一个字符串的每一个字符都在 allowed 中,就称这个字符串是 一致字符串

请你返回 words 数组中 一致字符串 的数目。

 

示例 1:

输入:allowed = "ab", words = ["ad","bd","aaab","baa","badab"]
输出:2
解释:字符串 "aaab" 和 "baa" 都是一致字符串,因为它们只包含字符 'a' 和 'b' 。

示例 2:

输入:allowed = "abc", words = ["a","b","c","ab","ac","bc","abc"]
输出:7
解释:所有字符串都是一致的。

示例 3:

输入:allowed = "cad", words = ["cc","acd","b","ba","bac","bad","ac","d"]
输出:4
解释:字符串 "cc","acd","ac" 和 "d" 是一致字符串。

 

提示: