Thank you, Jeff. We delivered strong performance in 2019 with growth across all of our core business areas, double-digit earnings growth versus a year ago and strong execution across each pillar of our strategy. For 2020, we aim to continue our momentum by executing well on our strategic priorities across MS, SMA, biosimilars and our pipeline, with a priority on aducanumab. We are actively preparing for the potential launch of aducanumab with an initial focus on the US. This includes implementing a thorough go-to-market model, hiring the sales force, building out our medical teams and preparing for market access. In addition, we are actively engaging with regulators outside of the US, including Europe and Japan. Beyond aducanumab, our pipeline is maturing. We now have six programs in Phase III and 27 clinical programs overall, an increase from 17 just three years ago. We have multiple near-term opportunities for value creation, including in Alzheimer's disease, ALS, stroke, lupus, ophthalmology and biosimilars, as we aim to build a multi-franchise portfolio. Between now and the end of 2021, we expect 11 mid-to-late stage data readouts, including Phase III readouts for tofersen in ALS, BIIB111 in choroideremia and BIIB093 in large hemispheric infarction, and eight Phase II readouts across MS, Alzheimer's disease, Parkinson's disease, ophthalmology, schizophrenia, acute neurology and neuropathic pain. As the leader in neuroscience, with asymmetric [ph] core capabilities, we believe that no other company is better positioned to continue to deliver breakthrough therapies for diseases of the nervous system to address a significant and growing unmet medical need. We'll continue to execute on our core strategy to build a multi-franchise portfolio across our core and emerging growth areas. I want to reiterate our commitment to maximizing returns to our shareholders and bringing innovative therapies to patients over the long term. This demands that we continue to look at capital efficiently, effectively and appropriately. As we have demonstrated in the past, we will always strive to have an optimal capital structure, as well as aim for superior returns from the investment we make. I'd like to take a moment to discuss how we brought the purpose as an organization as we aim to pioneer science for the betterment of humanity. This includes doing the right thing for patients, our employees, the environment and the community, all of which we believe contributes to a long-term sustainable shareholder value. I am proud of what Biogen stands for, and I believe this approach positions us well to be a sustainable organization over the long term, as we remain focused on being the leader in neuroscience to address the tremendous societal needs in this space. Finally, I would like to thank our employees around the world, who are dedicated to making a positive impact on patients' lives, and all of the physician, caregivers and participants in our clinical development programs. Our past and future achievements could not be realized without their passion and commitment. We will now open the call for questions.