feel free to provide a specific
suggestion

per the current directions "The length of all words provided in the list will be >= n." the Kata was written to be a 7/8 level difficulty, so corner cases such as the one you mention or e.g. multiple words having the same letter at the nth position are not tested

added

added

great, thanks

without my "suggestion" your current test cases do not adequately qualify a solution based on the requirements of the kata i.e. the kata has an issue. sorry if this information has offended you, that was not the intent.

if accepting solutions that don't satisfy the kata's requirements isn't an issue then i must be misundertanding the distinction

there should be a test case for an instance that requires the digits be summed > 2 times:

e.g.

root(4534543452) => 39 => 12 => 3

Test case added, thanks