Count Consecutive Characters Given a string containing only letters, output the length of the longest run of consecutive alphabetical letters the word contains, where order does not matter. An example algorithm may sort the word, remove duplicates, and then output the length of the longest run.

Test Cases

watch -&gt; 1
stars -&gt; 3
antidisestablishmentarianism -&gt; 3
backdoor -&gt; 4
a -&gt; 1
tutorials -&gt; 4


For example, antidisestablishmentarianism contains the letters abdehilmnstr. The longest runs are lmn and rst, both of length 3.

Notes

You may take all lowercase, all uppercase, or mixed-case letters as input, but the case cannot encode information about the word (i.e. you cannot make the first n characters capitalized where n is the length of the longest run).

This is code-golf, so shortest answer in bytes wins.
Jelly, &nbsp;10 9 8 7&nbsp; 6 bytes

OṬṣ0ZL


Try it online!

9 was using Sok's method: ṢQẆẇƇØaṪL

How?

OṬṣ0ZL - Link: list of (single-case) characters  e.g.  codegolf
O      - ordinal (vectorises)           [99,111,100,101,103,111,108,102]
 Ṭ     - untruth (1s at those indices)  [0,0,0,...,1,1,1,1,1,0,0,0,0,1,0,0,1]
       -                                 ^         ^       ^         ^     ^
       -                   i.e. indices: 1        99     103       108   111
   0   - literal zero
  ṣ    - split at                       [[],[],[],...,[1,1,1,1,1],[],[],[],[1],[],[1]]
    Z  - transpose                      [[1,1,1],[1],[1],[1],[1]]
     L - length                         5