You are given an array of strings arr. A string "s" is formed by the concatenation of a subsequence of arr that has unique characters. Return the maximum possible length of s. NOTE: A subsequence is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.
Input Format
["cha","r","act","ers"]
Output Format
6
Constraints
1 <= arr.length <= 16 1 <= arr[i].length <= 26 arr[i] contains only lowercase English letters.
Notice
NA
Example
Input
abcdefghijklmnopqrstuvwxyz
Output
26