Input (grade 13): Although his parents were Jewish, his father was a dental technician and his mother a dentist, which allowed the family to live outside the Pale of Settlement to which most Jews in Russia were restricted at the time.
Output (grade 10): His father was a dental technician, and a cantor in the local synagogue. His mother was a dentist, which allowed the family to live outside the Pale of Settlement to which most Jews in Russia were restricted at the time.