our adjusted ebitda decreased $ 451 million to $ 209 million for the year ended december 31 , 2019 , from $ 660 million for the year ended december 31 , 2018 , primarily due to the osb pricing and shipment declines , partially offset by the smartside® strand revenue growth . demand for building products demand for our products correlates to a significant degree to the level of new home construction activity in north america , which historically has been characterized by significant cyclicality . the u.s. census bureau reported that actual single and multi-family housing starts in 2019 were about 3 % higher than in 2018 . single-family housing starts were about one percent higher than in 2018 . we believe that the level of building continues to be impacted by a lack of available labor . while near-term residential construction is constrained in the u.s. , positive long-term fundamentals exist . increased immigration , the changing age distribution of the population , and historically low-interest rates are expected to lead to more household formations . the chart below , which is based on data published by u.s. census bureau , provides a graphical summary of new housing starts for single and multi-family in the u.s. showing actual and rolling five and ten-year averages for housing starts . 22 supply and demand for siding smartside® siding is a specialty building material and is subject to competition from various siding technologies , including vinyl , stucco , wood , fiber cement , brick , and other . we believe we are the largest manufacturer to the $ 800 million engineered wood siding market . the overall siding market is estimated to be over $ 10 billion . we have consistently grown our smartside® strand siding above the underlying market growth rates . smartside® strand is generally less sensitive to new housing market cyclicality since roughly 60 % of its demand comes from other markets , including : sheds , retail , and repair and remodel . our growth in this market depends upon continued displacement of vinyl , wood fiber , cement and stucco alternatives , our product innovation and our technological expertise in wood and wood composites to address the needs of our customers . supply and demand for osb osb is a commodity product , and it is subject to competition from manufacturers worldwide . product supply is influenced primarily by fluctuations in available manufacturing capacity and imports . the ratio of overall osb demand to capacity generally drives price . critical accounting policies and significant estimates management 's discussion and analysis of financial condition and results of operations are based upon our consolidated financial statements , which have been prepared in accordance with u.s. gaap . the preparation of these financial statements requires management to make informed estimates and judgments that affect the reported amounts of assets , liabilities , revenues and expenses , and related disclosure of contingent assets and liabilities . our financial position and or results of operations may be materially different when reported under different conditions or when using different assumptions in the application of such policies . in the event estimates or assumptions prove to be different from actual amounts , adjustments are made in subsequent periods to reflect more current information . our significant accounting policies are disclosed in the consolidated financial statements and item 8 of this annual report on form 10-k. the following discussion addresses our most critical accounting policies , which are those that are both important to the portrayal of our financial condition and results of operations and that require significant judgment or use of complex estimates . long-lived assets property , plant and equipment , and long-lived assets ( including amortizable identifiable intangible assets ) are tested 23 for recoverability whenever events or changes in circumstances indicate that its carrying amount may not be recoverable , including but not limited to facility curtailments and asset abandonments . when such events occur , we group long-lived assets with other assets and liabilities at the lowest level for which identifiable cash flows exist . we compare the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset or asset group to the carrying amount of a long-lived asset or asset group . the cash flows are based on our best estimate of future cash flows derived from the most recent business projections . the significant assumptions used to determine estimated cash flows are the cash inflows and outflows directly resulting from the use of those assets in operations , including sales volume , product pricing , support costs , and other costs to operate . we recognize an impairment loss if the amount of the asset 's carrying value exceeds the asset 's estimated fair value . fair value is estimated primarily using discounted expected future cash flows on a market-participant basis . if we recognize an impairment loss , the adjusted carrying amount of the asset becomes its new cost basis . for a depreciable long-lived asset , the new cost basis is depreciated ( amortized ) over the remaining estimated useful life of that asset . our impairment loss calculations contain uncertainties because they require management to make assumptions and to apply judgment to estimate future cash flows and asset fair values . we have not made any material changes in our impairment loss assessment methodology in the periods presented . we do not believe a material change in the estimates or assumptions that we use to calculate long-lived asset impairments is likely . however , if actual results are not consistent with our estimates and assumptions used in estimating future cash flows and asset fair values , we may be exposed to losses that could be material . story_separator_special_tag adjusted ebitda increased $ 3 million ( or 12 % ) from 2017 , primarily due to the realization of price increases and reductions in manufacturing costs due to higher utilization across all ewp mills offset by increases in raw material costs , principally , lumber , veneer , and osb . south america our south america segment manufactures and distributes osb structural panel and siding products in south america and certain export markets . this segment has manufacturing operations in two countries , chile and brazil , and operates sales offices in chile , brazil , peru , columbia , and argentina . segment sales , adjusted ebitda , and adjusted ebitda margin for this segment were as follows : replace_table_token_18_th sales in this segment by product were as follows : replace_table_token_19_th percent changes in average sales prices and unit shipments for 2019 compared to 2018 are as follows : replace_table_token_20_th year ended december 31 , 2019 , compared to year ended december 31 , 2018 net sales decreased $ 2 million ( or one percent ) compared to 2018 due to pricing pressure from increased competition in export markets in south america and asia and unfavorable foreign currency fluctuations , partially offset by increases in local and export shipments . 31 adjusted ebitda decreased $ 6 million ( or 15 % ) from 2018 , primarily due to pricing pressure from increased competition and unfavorable foreign currency fluctuations . year ended december 31 , 2018 , compared to year ended december 31 , 2017 net sales increased $ 6 million ( or four percent ) from 2017 due to increased market penetration and osb price increases implemented in south america offset by decreased shipments in south america due to the slowing housing market in chile and continued economic weakness across south america . south america adjusted ebitda increased $ 7 million ( or 20 % ) from 2017 due to the osb price increases partially offset by operating costs associated with the start-up of our third mill in chile . other our other products segment includes our off-site framing operation entekra holdings , llc ( entekra ) , remaining timber and timberlands , and other minor products , services , and closed operations , which are not classified as discontinued operations . other net sales were $ 20 million for 2019 as compared to $ 11 million in 2018 . the increase from 2018 was due to our acquisition of a controlling interest in entekra in 2019 . adjusted ebitda was $ ( 11 ) million for 2019 as compared to $ ( 8 ) million for 2018 . other sales were $ 11 million for 2018 as compared to $ 12 million in 2017 . adjusted ebitda was $ ( 8 ) million for 2018 as compared to $ ( 6 ) million of adjusted ebitda for 2017 . general corporate and other expense , net general corporate and other expenses primarily comprise corporate overhead unrelated to business activities such as : wages and benefits , professional fees , insurance , and other expenses for corporate functions , including certain executive officers , public company activities , tax , internal audits , and other corporate functions . general corporate and other expense , net , was $ 30 million in 2019 as compared to $ 28 million in 2018 and 2017. the increase in 2019 as compared to 2018 was primarily due to increased costs associated with investments in transformation activities . impairments of long-lived assets during 2019 , we recorded $ 92 million of pre-tax impairment charges of our non-operating and operating long-lived assets . included within these impairment charges are $ 47 million related to non-operating assets located at val-d'or and st michel , quebec , canada ; cook , minnesota ; and silsbee , texas ; and $ 39 million related to an ewp facility producing lsl and osb and $ 5 million related to a siding facility that we expect to sell . these impairment charges reflect changes to anticipated usage of these facilities driven by market changes and improved operating efficiencies across our remaining facilities . impairments of long-lived assets were $ 11 million and $ 9 million in 2018 and 2017 , respectively . during 2018 , we recorded a loss on impairment of long-lived assets associated with a non-operating facility that was anticipated to be sold . other operating credits and charges , net for a discussion of other operating credits and charges , net , see note 14 of the notes to the consolidated financial statements included in item 8 of this annual report on form 10-k. 32 non-operating income ( expense ) for a discussion of non-operating income ( expense ) , see note 14 of the notes to the consolidated financial statements included in item 8 of this annual report on form 10-k. income taxes we recorded a tax benefit of $ 13 million in 2019 and a provision of $ 122 million in 2018 . for 2019 , the primary differences between the u.s. statutory rate of 21 % and the effective rate relate to state income tax , foreign tax rates , tax credits , uncertain tax positions , and changes in the valuation allowance . we paid $ 20 million and $ 90 million of income taxes net of tax refunds in 2019 and 2018 , respectively . legal and environmental matters for a discussion of legal and environmental matters involving us and the potential impact thereof on our financial position , results of operations and cash flows , see item 3 in this annual report on form 10-k as well as note 16 of the notes to the consolidated financial statements included in item 8 of this annual report on form 10-k. story_separator_special_tag to estimate when these unrecognized uncertain tax positions may need to be paid . as of december 31 , 2019 , the amount of uncertain tax positions excluded from the

liquidity and capital resources overview our principal sources of liquidity are existing cash and investment balances , cash generated by our operations , and our ability to borrow under such credit facilities as we may have in effect from time to time . we may also , from time to time , issue and sell equity , debt or hybrid securities , or engage in other capital market transactions . our principal uses of liquidity are paying the costs and expenses associated with our operations , servicing outstanding indebtedness , paying dividends , and making capital expenditures . we may also , from time to time , prepay or repurchase outstanding indebtedness or shares or acquire assets or businesses that are complementary to our operations . any such repurchases may be commenced , suspended , discontinued or resumed , and the method or methods of effecting any such repurchases may be changed at any time , or from time to time , without prior notice . operating activities during 2019 , we generated $ 159 million of cash from operations as compared to $ 511 million of cash from operations in 2018 . this change reflects the lower osb commodity pricing in 2019 compared to 2018 partially offset by tax refunds from prior years of $ 14 million received in 2019 and a $ 41 million reduction in pension contributions . at december 31 , 2019 , and december 31 , 2018 , we had working capital of $ 194 million and $ 147 million , respectively . changes in working capital primarily related to increases in our income tax receivables during 2019. investing activities during 2019 , net cash used for investing activities was $ 137 million as compared to $ 238 million in 2018 . capital expenditures were $ 163 million for 2019 , primarily related to the expansion of our siding business as well as growth and maintenance capital .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```liquidity and capital resources overview our principal sources of liquidity are existing cash and investment balances , cash generated by our operations , and our ability to borrow under such credit facilities as we may have in effect from time to time . we may also , from time to time , issue and sell equity , debt or hybrid securities , or engage in other capital market transactions . our principal uses of liquidity are paying the costs and expenses associated with our operations , servicing outstanding indebtedness , paying dividends , and making capital expenditures . we may also , from time to time , prepay or repurchase outstanding indebtedness or shares or acquire assets or businesses that are complementary to our operations . any such repurchases may be commenced , suspended , discontinued or resumed , and the method or methods of effecting any such repurchases may be changed at any time , or from time to time , without prior notice . operating activities during 2019 , we generated $ 159 million of cash from operations as compared to $ 511 million of cash from operations in 2018 . this change reflects the lower osb commodity pricing in 2019 compared to 2018 partially offset by tax refunds from prior years of $ 14 million received in 2019 and a $ 41 million reduction in pension contributions . at december 31 , 2019 , and december 31 , 2018 , we had working capital of $ 194 million and $ 147 million , respectively . changes in working capital primarily related to increases in our income tax receivables during 2019. investing activities during 2019 , net cash used for investing activities was $ 137 million as compared to $ 238 million in 2018 . capital expenditures were $ 163 million for 2019 , primarily related to the expansion of our siding business as well as growth and maintenance capital .
```    
 Suspicious Activity Report : our adjusted ebitda decreased $ 451 million to $ 209 million for the year ended december 31 , 2019 , from $ 660 million for the year ended december 31 , 2018 , primarily due to the osb pricing and shipment declines , partially offset by the smartside® strand revenue growth . demand for building products demand for our products correlates to a significant degree to the level of new home construction activity in north america , which historically has been characterized by significant cyclicality . the u.s. census bureau reported that actual single and multi-family housing starts in 2019 were about 3 % higher than in 2018 . single-family housing starts were about one percent higher than in 2018 . we believe that the level of building continues to be impacted by a lack of available labor . while near-term residential construction is constrained in the u.s. , positive long-term fundamentals exist . increased immigration , the changing age distribution of the population , and historically low-interest rates are expected to lead to more household formations . the chart below , which is based on data published by u.s. census bureau , provides a graphical summary of new housing starts for single and multi-family in the u.s. showing actual and rolling five and ten-year averages for housing starts . 22 supply and demand for siding smartside® siding is a specialty building material and is subject to competition from various siding technologies , including vinyl , stucco , wood , fiber cement , brick , and other . we believe we are the largest manufacturer to the $ 800 million engineered wood siding market . the overall siding market is estimated to be over $ 10 billion . we have consistently grown our smartside® strand siding above the underlying market growth rates . smartside® strand is generally less sensitive to new housing market cyclicality since roughly 60 % of its demand comes from other markets , including : sheds , retail , and repair and remodel . our growth in this market depends upon continued displacement of vinyl , wood fiber , cement and stucco alternatives , our product innovation and our technological expertise in wood and wood composites to address the needs of our customers . supply and demand for osb osb is a commodity product , and it is subject to competition from manufacturers worldwide . product supply is influenced primarily by fluctuations in available manufacturing capacity and imports . the ratio of overall osb demand to capacity generally drives price . critical accounting policies and significant estimates management 's discussion and analysis of financial condition and results of operations are based upon our consolidated financial statements , which have been prepared in accordance with u.s. gaap . the preparation of these financial statements requires management to make informed estimates and judgments that affect the reported amounts of assets , liabilities , revenues and expenses , and related disclosure of contingent assets and liabilities . our financial position and or results of operations may be materially different when reported under different conditions or when using different assumptions in the application of such policies . in the event estimates or assumptions prove to be different from actual amounts , adjustments are made in subsequent periods to reflect more current information . our significant accounting policies are disclosed in the consolidated financial statements and item 8 of this annual report on form 10-k. the following discussion addresses our most critical accounting policies , which are those that are both important to the portrayal of our financial condition and results of operations and that require significant judgment or use of complex estimates . long-lived assets property , plant and equipment , and long-lived assets ( including amortizable identifiable intangible assets ) are tested 23 for recoverability whenever events or changes in circumstances indicate that its carrying amount may not be recoverable , including but not limited to facility curtailments and asset abandonments . when such events occur , we group long-lived assets with other assets and liabilities at the lowest level for which identifiable cash flows exist . we compare the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset or asset group to the carrying amount of a long-lived asset or asset group . the cash flows are based on our best estimate of future cash flows derived from the most recent business projections . the significant assumptions used to determine estimated cash flows are the cash inflows and outflows directly resulting from the use of those assets in operations , including sales volume , product pricing , support costs , and other costs to operate . we recognize an impairment loss if the amount of the asset 's carrying value exceeds the asset 's estimated fair value . fair value is estimated primarily using discounted expected future cash flows on a market-participant basis . if we recognize an impairment loss , the adjusted carrying amount of the asset becomes its new cost basis . for a depreciable long-lived asset , the new cost basis is depreciated ( amortized ) over the remaining estimated useful life of that asset . our impairment loss calculations contain uncertainties because they require management to make assumptions and to apply judgment to estimate future cash flows and asset fair values . we have not made any material changes in our impairment loss assessment methodology in the periods presented . we do not believe a material change in the estimates or assumptions that we use to calculate long-lived asset impairments is likely . however , if actual results are not consistent with our estimates and assumptions used in estimating future cash flows and asset fair values , we may be exposed to losses that could be material . story_separator_special_tag adjusted ebitda increased $ 3 million ( or 12 % ) from 2017 , primarily due to the realization of price increases and reductions in manufacturing costs due to higher utilization across all ewp mills offset by increases in raw material costs , principally , lumber , veneer , and osb . south america our south america segment manufactures and distributes osb structural panel and siding products in south america and certain export markets . this segment has manufacturing operations in two countries , chile and brazil , and operates sales offices in chile , brazil , peru , columbia , and argentina . segment sales , adjusted ebitda , and adjusted ebitda margin for this segment were as follows : replace_table_token_18_th sales in this segment by product were as follows : replace_table_token_19_th percent changes in average sales prices and unit shipments for 2019 compared to 2018 are as follows : replace_table_token_20_th year ended december 31 , 2019 , compared to year ended december 31 , 2018 net sales decreased $ 2 million ( or one percent ) compared to 2018 due to pricing pressure from increased competition in export markets in south america and asia and unfavorable foreign currency fluctuations , partially offset by increases in local and export shipments . 31 adjusted ebitda decreased $ 6 million ( or 15 % ) from 2018 , primarily due to pricing pressure from increased competition and unfavorable foreign currency fluctuations . year ended december 31 , 2018 , compared to year ended december 31 , 2017 net sales increased $ 6 million ( or four percent ) from 2017 due to increased market penetration and osb price increases implemented in south america offset by decreased shipments in south america due to the slowing housing market in chile and continued economic weakness across south america . south america adjusted ebitda increased $ 7 million ( or 20 % ) from 2017 due to the osb price increases partially offset by operating costs associated with the start-up of our third mill in chile . other our other products segment includes our off-site framing operation entekra holdings , llc ( entekra ) , remaining timber and timberlands , and other minor products , services , and closed operations , which are not classified as discontinued operations . other net sales were $ 20 million for 2019 as compared to $ 11 million in 2018 . the increase from 2018 was due to our acquisition of a controlling interest in entekra in 2019 . adjusted ebitda was $ ( 11 ) million for 2019 as compared to $ ( 8 ) million for 2018 . other sales were $ 11 million for 2018 as compared to $ 12 million in 2017 . adjusted ebitda was $ ( 8 ) million for 2018 as compared to $ ( 6 ) million of adjusted ebitda for 2017 . general corporate and other expense , net general corporate and other expenses primarily comprise corporate overhead unrelated to business activities such as : wages and benefits , professional fees , insurance , and other expenses for corporate functions , including certain executive officers , public company activities , tax , internal audits , and other corporate functions . general corporate and other expense , net , was $ 30 million in 2019 as compared to $ 28 million in 2018 and 2017. the increase in 2019 as compared to 2018 was primarily due to increased costs associated with investments in transformation activities . impairments of long-lived assets during 2019 , we recorded $ 92 million of pre-tax impairment charges of our non-operating and operating long-lived assets . included within these impairment charges are $ 47 million related to non-operating assets located at val-d'or and st michel , quebec , canada ; cook , minnesota ; and silsbee , texas ; and $ 39 million related to an ewp facility producing lsl and osb and $ 5 million related to a siding facility that we expect to sell . these impairment charges reflect changes to anticipated usage of these facilities driven by market changes and improved operating efficiencies across our remaining facilities . impairments of long-lived assets were $ 11 million and $ 9 million in 2018 and 2017 , respectively . during 2018 , we recorded a loss on impairment of long-lived assets associated with a non-operating facility that was anticipated to be sold . other operating credits and charges , net for a discussion of other operating credits and charges , net , see note 14 of the notes to the consolidated financial statements included in item 8 of this annual report on form 10-k. 32 non-operating income ( expense ) for a discussion of non-operating income ( expense ) , see note 14 of the notes to the consolidated financial statements included in item 8 of this annual report on form 10-k. income taxes we recorded a tax benefit of $ 13 million in 2019 and a provision of $ 122 million in 2018 . for 2019 , the primary differences between the u.s. statutory rate of 21 % and the effective rate relate to state income tax , foreign tax rates , tax credits , uncertain tax positions , and changes in the valuation allowance . we paid $ 20 million and $ 90 million of income taxes net of tax refunds in 2019 and 2018 , respectively . legal and environmental matters for a discussion of legal and environmental matters involving us and the potential impact thereof on our financial position , results of operations and cash flows , see item 3 in this annual report on form 10-k as well as note 16 of the notes to the consolidated financial statements included in item 8 of this annual report on form 10-k. story_separator_special_tag to estimate when these unrecognized uncertain tax positions may need to be paid . as of december 31 , 2019 , the amount of uncertain tax positions excluded from the

