What is a bug

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Across
  1. 3. total
  2. 4. gone
  3. 7. totally
  4. 8. difficulty
  5. 10. general
  6. 11. conclude
  7. 13. несоответствие
  8. 16. plan
  9. 17. state
  10. 18. assume
  11. 19. happen
  12. 21. mention
Down
  1. 1. discuss
  2. 2. remember
  3. 4. meaning
  4. 5. electricity
  5. 6. serious
  6. 9. соглашение
  7. 12. непреднамеренный
  8. 14. absolutely
  9. 15. careful
  10. 20. block