Meaning:
- eightwothree -> 823 (answer 83)
- 4nineeightseven2 -> 49872 (answer 42)
- zoneight234 -> z18234 (answer 14)
I interpreted the instructions as saying to take the first match from the left and not count the overlaps.
Unfortunately this gives the same answer as the overlap interpretation on the examples given in the problem statement: all the overlaps occurred in the middle where they didn't matter.
If they had shown
oneight -> answer: 18
then I would have understood the spec.