The second question on R&D, first of all, I would advise investors to really look at the non-GAAP R&D number, because the GAAP number includes one-off expenses, such as acquisition related expense, escalation composition of the acquisition consideration paid to the teams of Easemob and Netless was classified as R&D expense in the income statement. So in terms of the non-GAAP R&D expense, it was 43% of revenues in this quarter. And we actually expect this to remain as around 40% level as well this year, as we continue to invest very heavily in R&D. So right now we have close to 1,000 employees that's excluding Easemob, which has about 200. And out of that 1,200, total employee base, about two-third are R&D employees, and they are working on a lot of things. I can roughly divide these things into three categories. The first one is quality improvements. On the front end are the SDK is the end user software side, right video/audio compression. How to minimize the video size while keeping high fidelity, how to lower CPU usage, how to reduce the size of the SDK, how to become more compatible with thousands of new devices coming out every year so these are the things the front-end team is working on. And then the back-end team as they work on the global network routing algorithms. How to deal with packet loss, how to deal with the failure of one server, one datacenter, one transmission line or in all one part of the whole network, how to scale up and down without affecting user experience, how to optimize cost structure, all of these things. The second category would be new products, things like technical classroom and content moderation for video is that you have two examples of the new products we released recently. And also, what Tony talked about in his opening remarks are these new products. And the three category will be to support of new use cases, when the new use cases they often requires new features to be developed, new demos, new templates, and deep optimization of all the technical details with developers and customers, so yes that’s a third direction. So all these things as you can see, they don't like translate one on one to revenue of our overall they enhance our competitiveness and they see overall breadths and depths of the platform. So there will be a gradual revenue impact. And as we scale as use cases, proliferate, we do expect, eventually R&D expense will come down as percentage through revenue. But we do not expect that to change significantly during the course of this year as we are still in the face of investment.