6728
The following is a comprehensive discography of English heavy metal band  Judas Priest  which currently consists of singer  Rob Halford  bassist Ian Hill dual lead/rhythm guitarists Glenn Tipton and Richie Faulkner and drummer Scott Travis .
 Judas Priest, Rob Halford
Please list all entity pairs containing a certain relationship in the given options.Output format is "word1, word2; 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:
 Judas Priest, Rob Halford