paul pullman is a great example.here's someone who says i'm going to expand the revenue by twice but half the environmental footprint at the same time i do that. i think people who challenge themselves and their organizations to continue to create economic value while thinking hard about the negative externalities of business and making sure they minimize the negative externalities, those are the kind of leaders who will set the example of what business need to be. we are fortunate we have examples of business leaders showing the way. we're studying the examples. we're making sure we inspire our students to think about that. we're also lucky that one of the great surprises i've had as dean of the harvard business school is i know our graduates have done very well in business but what's been amazing to me is to see how many of our graduates are so devoted to social enterprises -- if you think about the great hospitals, the great universities, k-12 charter schools -- we're seeing business leaders devoting themselves to