Thank you, Stephen. So again, to recap, overall revenue was up $41 million or 10.4% in the quarter. The organic growth approximates 7.5%, with 5.25% coming from full service and 2.25% coming from back-up and Ed advisory. Acquisitions added a further 4.5% growth in the quarter. And center closures offset top line growth by about 3%, while the pound and the euro strengthened against the dollar, adding just over 1% to the top line growth in the quarter. Gross profit increased to $108 million or 24.6% of revenue. And adjusted operating income increased to $54 million or 12.2% of revenue. On a segment basis, the back-up division expanded $6 million on the top line, and ed advisory was up $3 million, or 22%, from a combination of new client launches and expanded utilization by our existing clients. Revenue growth and margins can vary from quarter-to-quarter in both of these segments based on the timing of new client launches, the service utilization levels and the investments that we are making in the growth and service delivery. That said since the operating margins in both back-up and ed advisory are 2x to 3x what we earned in our full service centers, we continue to see their revenue growth and sustained operating performance contributing to margin expansion over time. Turning to full service. The $32 million increase in center revenue was driven by rate increases, enrollment gains and contributions from new centers. Operating margins, again, excluding the Q4 transaction cost were 8.8% in Q4, 2017, roughly consistent with 2016 levels with a few offsetting factors. The gains we've realized from an enrollment growth in our matured and ramping centers, disciplined pricing strategies and cost management and contributions from new and acquired centers are partially offset by the margin effects of the recently opened classes of lease consortium centers that are still in their ramp up stage. Overall, Q4 2017 overhead was $46 million compared to $42 million in 2016. Again excluding the transaction costs for the debt and secondary offerings that we had in acquisitions in 2016, this is essentially consistent with 2016 levels as a percentage of revenue. Interest expense $11.8 million in the quarter, it was roughly consistent too with last year as lower interest rates from two repricing during 2017 offset the incremental borrowings. As Dave mentioned, we at the end of October we also entered into a four year interest rates swap on $500 million of our floating rate term loan B debt to hedge our exposure to rising interest rates. The 2017 structural tax rate on adjusted net income came in at 24% for the year. And a slightly higher tax benefits from stock option exercises in the quarter than we had initiated estimated. This rate does not include any effects of tax reform due to the one time nature of the provisions under the reform that affect us. We generated operating cash flow of $236 million in 2017, compared to $213 million last year. The increase relates to improved core performance and working capital. But it was lower than our previous estimate primarily due to the additional $11 million liability for the transition tax on foreign earnings that we recorded in Q4, 2017 in conjunction with tax reform. After deducting maintenance CapEx, free cash flow totaled $200 million for 2017. Again as Dave outlined, we deployed our cash flow into center investments and acquisition. We also repurchased total of 2 million shares in 2017 both through open market purchases and the block trades in May and November. We ended 2017 at roughly 3.5x of net debt to EBITDA and expect that to tick down towards 3x by the end of 2018. Lastly, at 12/31/2017, we operated 1,038 centers with the capacity to serve 116,000 children. So now to add to the guidance headlines that Stephen previewed. Our outlook for 2018 anticipates revenue growth approximate in 8% to 10% over 2017. That includes low double digit revenue growth in our back-up division, 10% to 12% for the year. And top line growth in our Ed advisory services in the 15% to 20% range for the year. In our full service segment, we are planning to add a total of approximately 45 to 50 new centers in 2018 including organic, new and acquired centers. And our outlook also contemplates closing approximately 25 centers. A more typical run rate than we saw in 2017. On the operating side for 2018 in the full service, we expect to continue to gain approximately 1% to 2% from enrollment in our ramping and matured centers. And we project price increases averaging 3.5% to 4% across the P&L center network, while maintaining 1% spread between price and our cost increases. We, therefore anticipate that we'll regain the operating leverage that Stephen mentioned in the range of 50 to 100 basis points as a factors mitigating margin expansion in 2017 diminish over the course of the year. On some other key measure for the full year of 2018, we estimate amortization of $32 million, depreciation in the range of $17 million and stock compensation of around $15 million. Based on our outstanding borrowings and estimates of additional interest rate increases in 2018, we are projecting interest expense in the range of $48 million to $50 million. Now, let me touch on the expected structural tax rate for 2018 and the potential effects on Bright Horizons of Tax Reform. The headline is that while positive, the net effect will be modest for us in 2018 given the comparison to the structural tax rate for 2017, which benefited from the new rules regarding tax benefits on equity transactions. We estimate that the effective tax rate will approximate 23% in 2018, compared to 24% in 2017. Specifically, the reduction in the US federal tax rate will be partially offset by one, incremental taxes on foreign earnings and two, higher net effective state income tax rate. Most significantly the estimated impact of the tax benefits of stock option exercises is expected to be substantially lower in 2018, due to both the lower applicable tax rates and the projections of activity for eligible exercises. We estimate that we'll generate approximately $260 million to $270 million of cash flow from ops yielding around $220 million to $230 million of free cash flow after $45 million or so of estimated maintenance CapEx. Investments in our new center capital for centers opening in 2018 and in early 2019 are projected to total $45 million to $50 million in 2018. So the combination of all these factors lead to our projection that we'll generate adjusted net income in the range of $184 million to $187 million, and adjusted EPS in the range of $3.12 to $3.16 on projected weighted average shares of 59 million to 59.5 million. Looking specifically to Q1 of 18, we're projecting 8% to 9% top line growth, adjusted net income in the range of $41 million to $42 million and adjusted EPS in the range of $0.70 to $0.71 a share. So with that Omar, we are ready to go to Q&A.