Question: Of what nationality are both Dentsply Sirona and Omnicom Group?

full_context: Document 1: Sears Holdings: The Sears Holdings Corporation is an American holding company headquartered in Hoffman Estates, Illinois, a suburb of Chicago. It is the owner of retail store brands Sears and Kmart, and was founded after the latter purchased the former in 2005. Sears Holdings also owns the brands Kenmore and DieHard. A sale of Craftsman to Stanley Black and Decker occurred in March of 2017. Sears retains the rights to sell Craftsman tools for 15 years from the date of sale through the purchase of tools from their established suppliers. Sears Holdings operates 1,503 retail locations under the mastheads of Sears, Kmart, and their subsidiaries, such as auto centers and pharmacies, in all 50 states, Puerto Rico, and Guam. As of 2014, it is the 18th-largest retailing company in the United States.
Document 2: GroupM: GroupM is the world’s largest advertising media company in terms of billings, also commonly known as "The Big One". It is headquartered in New York City with over 24,000 employees and 400 global offices in 81 countries. GroupM was formed in 2003 by WPP Group to serve as the parent company of WPP's media agencies including Maxus, MEC, MediaCom, Mindshare, QUISMA, Xaxis, Outrider, Catalyst, Quasar, IEG, Movent, Vocanic, Essence Digital Inc, and Plista. It handles over 32% of the world's media billings making it the world's largest media investment management operation. Kelly Clark is Global CEO of GroupM and manages the worldwide operations including the management of GroupM’s agencies worldwide. Irwin Gotlieb is Chairman of GroupM and focuses on the overall strategic direction of GroupM.
Document 3: Nordson Corporation: Nordson Corporation is an American multinational corporation that designs and manufactures dispensing equipment for consumer and industrial adhesives, sealants and coatings. The company also manufactures equipment used in the testing and inspection of electronic components as well as technology-based systems for curing and surface treatment processes. The company is headquartered in Westlake, Ohio, and has direct operations and sales-support offices in approximately 30 countries.
Document 4: CEREC: CEREC or Cerec (Chairside Economical Restoration of Esthetic Ceramics, or CEramic REConstruction) is a method of CAD/CAM dentistry developed by W. Mörmann and M. Brandestini at the University of Zurich in 1980 for creating dental restorations. Using CAD/CAM (computer-aided design and computer-aided manufacturing), this process allows dentists to construct, produce, and insert individual ceramic restorations directly at the point of treatment (chairside) in a single appointment, rather than over multiple appointments with lab side working between. The first applications were successfully carried out on patients in 1985. The Cerec name is also a brand name of the Sirona companies (as of 2016 Dentsply Sirona) (Sirona Australia, Sirona Germany, Sirona USA, and others), because Sirona grew out of the exclusive licensing of the system by Siemens.
Document 5: Omnicom Group: Omnicom Group, Inc. is an American global marketing and corporate communications holding company, headquartered in New York City.
Document 6: Proposed merger of Publicis and Omnicom: The proposed merger of Publicis and Omnicom was a proposed advertising industry merger between Publicis and Omnicom, announced on July 28, 2013. The resulting company would have been called Publicis Omnicom Group, and would been the world's biggest advertising group with market capitalisation of $35.1 billion, pro-forma revenue of $22.7 billion, and more than 130,000 employees across the world. After the merger, Publicis Omnicom and WPP would have been the largest advertising groups in the world., followed at a distance by Dentsu and Interpublic Group of Companies. The Publicis and Omnicom chief executives heralded the proposed operation as a "merger of equals" saying that Publicis and Omnicom shareholders will each hold about 50 percent of the new group's equity. The group would have had head offices in Paris and New York.
Document 7: Group O: Group O, Headquartered in Milan, Illinois, is one of the largest Hispanic-owned companies in the U.S. and a provider of managed products and services, specializing in Marketing Services, Print Management, Business Analytics, Decision Sciences, Business Process Outsourcing, Managed Services, Packaging, Supply Chain and Third-Party Logistics (3PL). Founded in 1974, Group O has grown to approximately 1,500 employees across 34 U.S. facilities. The company targets a broad range of industries, including: food and beverage, telecommunications, manufacturing, consumer packaged goods, financial services, pharmaceutical, health care, retail and technology. The company’s major clients include AT&T, Bristol-Myers Squibb, Caterpillar, Frito-Lay, Kraft Foods, Microsoft, PepsiCo, and Staples.
Document 8: Sirona Dental Systems: Sirona Dental Systems Inc. (Sirona) was a global dental equipment manufacturer, and the world's largest dental equipment provider, which used to be part of Siemens. It became an independent company in 1997. The company is headquartered in Long Island City, New York. So far, it has facilities in over 17 countries and serves over 100 countries and districts. In 2011, the company was ranked at 27th in the list of America's Best Small Companies by Forbes. The company built the world's first dental X-ray unit, REKORD. In 2013, the company was awarded the Top Employer Award for Germany, Austria and Engineer in 2013. Its subsidiary in China, Sirona China, was given Top Employer China 2014. In 2014, it won the Good Design Award (Chicago) 2013 for its excellence design of two products.
Document 9: Dow Corning: Dow Corning is an American multinational corporation headquartered in Midland, Michigan, United States. Originally established as a joint venture between the Dow Chemical Company and Corning Incorporated, it is now owned by DowDuPont and specializes in silicone and silicon-based technology, and is the largest silicone product producer in the world.
Document 10: DDB Mudra: The DDB Mudra Group, a part of the DDB Worldwide Communications Group, is India's first and largest integrated marketing communications and services network. DDB Worldwide is owned by Omnicom Group Inc, one of the world's largest advertising holding companies.It was earlier known as Mudra Communications Limited and Mudra India. It also started Mudra Institute of Communications Ahmedabad which is considered India's first academic institution dedicated to communications and advertising studies. In 2011, Mudra group was acquired by Omnicom Group, subsequently rebranded as DDB Mudra group and merged with DDB Worldwide. As an advertising agency it is credited with handling successful campaigns of brands and products such as Castrol, Dabur, Future Group, Gulf Oil, and Volkswagen.
Document 11: DDB Worldwide: DDB Worldwide Communications Group Inc., known internationally as DDB, is a worldwide marketing communications network. It is owned by Omnicom Group Inc, one of the world's largest advertising holding companies (revenues US$12.69B according to "Advertising Age" in April 2008). The international advertising networks Doyle Dane Bernbach and Needham Harper merged their worldwide agency operations to become DDB Needham in 1986. At that same time the owners of Doyle Dane Bernbach, Needham Harper and BBDO merged their shareholdings to form the worldwide holding company Omnicom. In 1996, DDB Needham became known as DDB Worldwide.
Document 12: Patterson Companies: Patterson Companies Inc is a medical supplies conglomerate primarily in the business of veterinary and dental products (ranging from xray equipment to consumable products, dental consumables make up the biggest part of the dental industry). Since 2003 it also distributes general medical rehabilitative devices like braces and wheel chairs. Traditionally a dental company it diversified its business at the turn of the millennium when it acquired 55-year-old company JA Webster Inc, a distributor of veterinary products. That business segment (now known as Patterson Veterinary) currently distributes equipment (diagnostic and surgical) and medicine (anaesthetics, vaccines). The company operates directly in only the US and Canada (in Canada through subsidiaries Sammons Preston Canada and Patterson Dental Canada).
Document 13: Dentsply Sirona: Dentsply Sirona is an American dental equipment maker and dental consumables producer that markets its products in over 120 countries (factories in 21 countries). It is a leader in consumable dental products. The present company is largely the result of a merger in 1993 in which Gendex Corporation acquired Dentsply International Inc. for $590 million.
Document 14: Dana Incorporated: Dana Incorporated is an American worldwide supplier of drivetrain, sealing, and thermal-management technologies. Founded in 1904 and based in Maumee, Ohio, the company employs nearly than 29,000 people in 34 countries on six continents. In 2016, Dana generated sales of nearly $5.8 billion. The company is included in the Fortune 500.
Document 15: TBWA Worldwide: TBWA Worldwide is an international advertising agency whose main headquarters are in Midtown Manhattan, New York City, United States. The agency is a unit of Omnicom Group, the world's largest advertising agency holding company. It was founded in 1970 in Paris, France, by William G. Tragos (American, Management), Claude Bonnange (French, Marketing), Uli Wiesendanger (Swiss, Creation), and Paolo Ajroldi (Italian, Client Services). The first letter of each founder's name provided the initials for the new organization. They were purchased by the Omnicom Group in 1993.
ground_truth: American