Question: Which restaurant focuses more on just pizza, Valentino's and Imo's Pizza?

Context paragraphs:
Pizza 73: Pizza 73 is a Canadian restaurant chain that offers a number of different styles of pizza, along with chicken wings.  It has been operated by Pizza Pizza since 2007.  Toronto-based Pizza Pizza had acquired the restaurant for a total of $CAN70.2 million.  There are 89 locations throughout Western Canada, which include the provinces of British Columbia, Alberta, and Saskatchewan.  The restaurant's name originates from its original phone number: 473–7373.  Founded by David Tougas and Guy Goodwin in 1985, Pizza 73 is headquartered in Edmonton, Alberta, Canada.

Valentino's: Valentino's is a regional Italian restaurant chain based in Lincoln, Nebraska.  Valentino's was founded by Val and Zena Weiler in 1957.  The restaurant was purchased by two Lincoln families in 1971 and began franchising additional locations.  The first carry-out store opened in 1990, and many of the full-scale restaurants converted to the buffet concept in the early-2000s.

Peppes Pizza: Peppes Pizza is a Norwegian pizza chain that serves American style and Italian style pizza.  Peppes is the largest pizza chain in Scandinavia.  The restaurant was founded by two Americans, Louis Jordan and his wife Anne from Hartford, Connecticut.  The restaurant chain is part of Umoe Catering As which consists of restaurants such as Burger King, TGI Fridays, La Baguette and Cafe Opus.  Peppes Pizza is one of the first restaurants that brought foreign food to Norway.  9 million pizzas are served by Peppes each year with deliveries in 11 cities in Norway.  Their menu was first put online in March 1995.  The servings have been described as enough for two people and that the pizza chain is "a cut above the rest".

Pizza Ranch: The Pizza Ranch, Inc., founded in 1981, is a "fast casual" restaurant chain.  Pizza Ranch offers pizza, chicken, a salad bar, and a pizza and chicken buffet.  Pizza Ranch has over 200 locations in Colorado, Illinois, Iowa, Kansas, Michigan, Minnesota, Missouri, Montana, Nebraska, North Dakota, South Dakota, Wisconsin, and Wyoming.  Pizza Ranch is the largest regional pizza franchise in Iowa, Minnesota, North Dakota, and South Dakota.

Nairi Sedrakyan: Nairi Sedrakyan (born 1961 in Ninotsminda, USSR) is an Armenian mathematician involved in national and international Olympiads of mathematics, having been the president of Armenian Mathematics Olympiads, the Leader of Armenian IMO Team, jury member and problem selection committee member of International Mathematical Olympiad, jury member and problem selection committee member of Zhautykov International Mathematical Olympiad (ZIMO), jury member and problem selection committee member of the 1st International Olympiad of Metropolises, the president of International Mathematical Olympiad Tournament of the Towns in Armenia.  He has also authored a large number of problems proposed in these Olympiads.  Nairi Sedrakyan is the author of one of the hardest problems ever proposed in the history of International Mathematical Olympiad, 5th problem of 37th International Mathematical Olympiad.  This problem is considered as one of the hardest problems ever, because none of the members of the strongest teams, i.e. National Olympic Teams of the USA, Russia or China has succeeded to solve it correctly.  Moreover, the National Olympic Team of People's Republic of China has obtained a cumulative result equal to 0 points and was ranked the 6th in the final ranking of the countries instead of the usual 1st or 2nd place.  The British 2014 film X+Y, released in the USA as A Brilliant Young Mind, inspired by, Beautiful Young Minds focuses on an English mathematical genius chosen to represent the United Kingdom at the IMO.  In the film this problem is stated to be the hardest problem ever proposed in the history of International Mathematical Olympiad (minutes 9:40-10:30).  Other outstanding results of the author are having 4 problems in the Shortlist of the worldwide selected 27 problems of the 40th IMO (1999) in Romania and having 5 medals winner students in 41st IMO in South Korea, i.e. 2 silver medals and 3 bronze medals.  Moreover, only 1 point was missing for Sevak Mkrtchyan to obtain a Gold Medal (currently he is an assistant professor of mathematics in United States, Sevak received his PhD in mathematics from University of California, Berkley).  Nevertheless, Arthur Barkhoudarian, one of the first students of Nairi Sedrakyan has received a Gold Medal in International Mathematical Olympiad, later on Arthur received his PhD degree in mathematics from Charles University in Prague.  As all winner students were from the same school, where Nairi Sedrakyan was teaching mathematics, the government of the Republic of Armenia gave to the author the title of the best teacher of the Republic of Armenia and he received a special gift from the Prime Minister.

JS Food Plan: JS Food Plan Co, Ltd. (commonly referred to as "JS" (which is an acronym for the Korean name Jae Sang) (hangul:제이에스 푸드플랜) is a franchised Korean pizza company headquartered in Yeoeuido-Dong Yeongdeungpo-gu, Seoul, Korea, established in 1998 the company is currently CEO'd by Jeong Jae Sang (정재상).  Its brand name is Pizza Segyero.  (hangul:피자 세계로) In 2005, the company became an international franchise when it expanded to Beijing, China.  The company is comparable to pizza restaurant chains such as Hankook Pizza Hut, Hankook Mr. Pizza, Chicken Nara, Domino Pizza Korea, Pizza Etang and Reach Beam.

Imo's Pizza: Imo's Pizza is a U.S. chain of pizza restaurants based in the greater St. Louis, Missouri area.  It is headquartered in St. Louis, Missouri.

Sir Pizza: Sir Pizza is an United States chain of pizza restaurants.  Wendell Swartz opened the original restaurant in Lafayette, Indiana in 1957 under the name of Pizza King.  Sir Pizza was incorporated in 1965.  In 1966, Robert Swartz, Wendell's brother, expanded Pizza King outside of Indiana under the name of "Sir Pizza".  In Indiana, they are franchised under the "Pizza King" name, one of two chains in Indiana using that name.

California-style pizza: California-style pizza (also known as California pizza or Gourmet pizza) is a style of single-serving pizza that combines New York and Italian thin crust with toppings from the California cuisine cooking style.  Its invention is generally attributed to chef Ed LaDou, and Chez Panisse, in Berkeley, California.  Wolfgang Puck, after meeting LaDou, popularized the style of pizza in the rest of the country.  It is served in a number of California Cuisine restaurants.  Such restaurant chains as California Pizza Kitchen, Extreme Pizza, and Sammy's Woodfired Pizza are three major pizza franchises associated with California-style pizza.  Nancy Silverton's Pizzeria Mozza is also a popular California-style pizza restaurant in Los Angeles.

Louie Mueller Barbecue: Louie Mueller Barbecue is a barbecue restaurant in Taylor, Texas.  Called "the epitome of Texas barbecue" by "The New York Times", the restaurant focuses on beef brisket, beef ribs, hand made beef sausages, pork ribs, and other smoked meats.  Louie Mueller has been in operation since 1946 and became its own entity in 1949.  Its current location, inhabited since 1959, was formerly a gymnasium in downtown Taylor.  The establishment is named for its original owner, and uses native post oak wood as fuel in its pits.  In 2013, a fire destroyed the original brick pit at the restaurant's location, though other pits were unscathed.

Supporting paragraphs: Valentino's Imo's Pizza
Answer: Imo's Pizza