644
The riding of Calgary Centre has been vacant since May 30 2012 when Lee Richardson resigned to accept a position as principal secretary to  Alberta  Premier  Alison Redford  .
 employee of: Alberta, Alison Redford
Given a phrase that describes the relationship between two words, extract the words and the lexical relationship between them. The output format should be "relation1: word1, word2; relation2: word3, word4". 
Option: cities of residence, top members employees, members, alternate names, origin, state or provinces of residence, title of person, spouse, city of headquarters, NA, founded by, state or province of headquarters, employee of, countries of residence, country of birth, founded, subsidiaries, country of headquarters 
Text: {0} 
Answer:
 employee of: Alberta, Alison Redford