470
While she would go on lecture tours , Houghton and Charlotte would exchange letters and spend as much time as they could together before she left .
 person: Houghton; person: Charlotte
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Houghton; person: Charlotte