Read this: Washington University in St. Louis (Wash. U., or WUSTL) is a private research university located in St. Louis, Missouri, United States. Founded in 1853, and named after George Washington, the university has students and faculty from all 50 U.S. states and more than 120 countries. Twenty-five Nobel laureates have been affiliated with Washington University, nine having done the major part of their pioneering research at the university. Washington University's undergraduate program is ranked 15th by U.S. News and World Report. The university is ranked 32nd in the world by the Academic Ranking of World Universities.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): How many Nobel laureates have been affiliated with Washington University?
Twenty-five