35081
The planners are also looking at ways America could use tactical nuclear weapons to penetrate Iran 's heavily reinforced underground uranium enrichment complex at Natanz .
 location contains: Iran, Natanz
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:  Iran, Natanz 
Answer:
 location contains: Iran, Natanz