30010
President Richard M. Nixon and Henry A. Kissinger , then the national security adviser , were imaginative enough to accept the invitation to visit China from Chairman Mao Zedong and Prime Minister Zhou Enlai , even though neither Ping-Pong nor a simple visit touched on the basic issues between China and the United States .
 nationality: Zhou Enlai, China; nationality: Mao Zedong, China; nationality: Mao Zedong, China; nationality: Zhou Enlai, China
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: ethnicity, place lived, geographic distribution, company industry, country of administrative divisions, administrative division of country, location contains, person of company, profession, ethnicity of people, company shareholder among major shareholders, sports team of location, religion, neighborhood of, company major shareholders, place of death, nationality, children, company founders, company founded place, country of capital, company advisors, sports team location of teams, place of birth 
Text: {0} 
 Entity Pairs:  Zhou Enlai, China; Mao Zedong, China; Mao Zedong, China; Zhou Enlai, China 
Answer:
 nationality: Zhou Enlai, China; nationality: Mao Zedong, China; nationality: Mao Zedong, China; nationality: Zhou Enlai, China