Given an array A of strings made only from lowercase letters, return a list of all characters that show up in all strings within the list (including duplicates). For example, if a character occurs 3 times in all strings but not 4 times, you need to include that character three times in the final answer.
You may return the answer in any order.
Example 1:
Input: ["bella","label","roller"] Output: ["e","l","l"]
Example 2:
Input: ["cool","lock","cook"] Output: ["c","o"]
Note:
<li><code>1 <= A.length <= 100</code></li>
<li><code>1 <= A[i].length <= 100</code></li>
<li><code>A[i][j]</code> is a lowercase letter</li>