15500
He became so well renowned for his work that shortly after Cornelius was approached by Joseph Saxton to create a silver plate for his daguerreotype of  Central High School  in  Philadelphia  .
 city of headquarters: Central High School, Philadelphia
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:
 city of headquarters: Central High School, Philadelphia