So tomorrow, when we exit these gates, we will take with us not only our GPAs or whoops prizes or capacity to write a twenty page paper in one night, but also our grit and determination our ability to face the inevitable challenges ahead.We will of course also take with us our understanding of very useful theoretical models and hypothetical thought experiments .We have much to be grateful for, thank you Harvard for giving us friends to wake us up for our nine am finals, for giving us grad students to lead us through full hours of silence and section. So family and friends , take out your cameras , open your arms for that hug and join me in celebrating the class of 2018.