(In reply to re(2): possible solution
1.".I assumed that 'only two distinct digits' meant exactly two for "..
AND RIGHTLY SO.
Anyone with common sense would object to describing 0 (zero)
as two-distinct-digit number.
When anyone asks you "tea or coffee?" only professional nitpicker might respond with a clarifying question
"Is the or inclusive or exclusive?"
2. Re your remark - d3 or d4 - I felt like 3.5 and was about to comply with your suggestion, but apparently was too slow.
No big deal.
3. I missed the "Jim" part - please explain...