Preunstructing or Preinstructing: How To spell?

The word Preunstructing is misspelled against Preinstructing, which is present continuous of "Preinstruct"

Word contains consecutive vowels 'EI' in between alphabets pr & nstructing is misspelled as 'EU'
Wrong Spelling:  pr-eu-nstructing 
Correct Spelling:  pr-ei-nstructing 
Check more misspelled words of Preinstructing to spell it correct.