1260
A pair " ( G , K ) " is called a " strong Gelfand pair " if the pair ( " G " × " K " , Δ " K " ) is a Gelfand pair , where Δ " K " ≤ " G " × " K " is the diagonal subgroup : { " ( k , k ) " in " G " × " K " : " k " in " K " .
 person: Gelfand; person: Gelfand
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: Gelfand; person: Gelfand