item 1b . unresolved staff comments item 2 . properties the table below provides a summary of our containerboard mills , the principal products produced and each mill 2019s year-end 2011 annual practical maximum capacity based upon all of our paper machines 2019 production capabilities , as reported to the af&pa : location function capacity ( tons ) counce , tn . . . . . . . . . . . . . . . . . . . . . . . . . kraft linerboard mill 1043000 valdosta , ga . . . . . . . . . . . . . . . . . . . . . . . kraft linerboard mill 556000 tomahawk , wi . . . . . . . . . . . . . . . . . . . . . . semi-chemical medium mill 538000 filer city , mi . . . . . . . . . . . . . . . . . . . . . . . semi-chemical medium mill 438000 .

Table: location function kraft linerboard mill kraft linerboard mill semi-chemical medium mill semi-chemical medium mill capacity ( tons ) 1043000 556000 538000 438000 counce tn valdosta ga tomahawk wi filer city mi filer city mi filer city mi total 2575000

we currently own our four containerboard mills and 44 of our corrugated manufacturing operations ( 37 corrugated plants and seven sheet plants ) . we also own one warehouse and miscellaneous other property , which includes sales offices and woodlands management offices . these sales offices and woodlands management offices generally have one to four employees and serve as administrative offices . pca leases the space for four corrugated plants , 23 sheet plants , six regional design centers , and numerous other distribution centers , warehouses and facilities . the equipment in these leased facilities is , in virtually all cases , owned by pca , except for forklifts and other rolling stock which are generally leased . we lease the cutting rights to approximately 88000 acres of timberland located near our valdosta mill ( 77000 acres ) and our counce mill ( 11000 acres ) . on average , these cutting rights agreements have terms with approximately 12 years remaining . our corporate headquarters is located in lake forest , illinois . the headquarters facility is leased for the next ten years with provisions for two additional five year lease extensions . item 3 . legal proceedings during september and october 2010 , pca and eight other u.s . and canadian containerboard producers were named as defendants in five purported class action lawsuits filed in the united states district court for the northern district of illinois , alleging violations of the sherman act . the lawsuits have been consolidated in a single complaint under the caption kleen products llc v packaging corp . of america et al . the consolidated complaint alleges that the defendants conspired to limit the supply of containerboard , and that the purpose and effect of the alleged conspiracy was to artificially increase prices of containerboard products during the period from august 2005 to the time of filing of the complaints . the complaint was filed as a purported class action suit on behalf of all purchasers of containerboard products during such period . the complaint seeks treble damages and costs , including attorney 2019s fees . the defendants 2019 motions to dismiss the complaint were denied by the court in april 2011 . pca believes the allegations are without merit and will defend this lawsuit vigorously . however , as the lawsuit is in the early stages of discovery , pca is unable to predict the ultimate outcome or estimate a range of reasonably possible losses . pca is a party to various other legal actions arising in the ordinary course of our business . these legal actions cover a broad variety of claims spanning our entire business . as of the date of this filing , we believe it is not reasonably possible that the resolution of these legal actions will , individually or in the aggregate , have a material adverse effect on our financial condition , results of operations or cash flows. .

Question: what is the total number of containerboard mills and corrugated manufacturing operations?
Answer: 48
Calculation: add(const_4, 44)