Question: The circuit that held the Rothmans 50,000 hosted how many stagings of the British Grand Prix?

full_context: Document 1: 2016 British GT Championship: The 2016 British GT Championship will be the 24th British GT Championship. The season will begin on 17 April at Brands Hatch and finish on 11 September at Donington Park, after nine rounds held over seven meetings. After using Avon Tyres since 2006, the championship will switch to Pirelli tyres this season in order to mirror that of other GT3 and GT4 categories promoted by Stéphane Ratel Organisation.
Document 2: 1949 BRDC International Trophy: The first BRDC International Trophy meeting, formally titled the Daily Express International Trophy, was held on 20 August 1949 at the Silverstone Circuit, England. It was the first race meeting to only use the former airfield's perimeter roadways, rather than the main runways. The event was held over two heats of 20 laps and one final of 30 laps of the Grand Prix circuit. The final was won by Italian Alberto Ascari, who would go on to win the World Championship of Drivers twice. In addition to the main Formula One-regulation competition, the meeting also contained events for 500 cc racing cars and production cars. The race meeting was attended by over 100,000 people, but was marred by the death of St. John Horsfall in an accident on the 13th lap of the final race.
Document 3: 2015 British Grand Prix: The 2015 British Grand Prix (formally known as the 2015 Formula 1 British Grand Prix) was a Formula One motor race that took place on 5 July 2015 at the Silverstone Circuit in Silverstone, United Kingdom. The race was the ninth round of the 2015 season, and marked the 70th running of the British Grand Prix, and the 51st time that the race was held at the Silverstone Circuit.
Document 4: Brighton Speed Trials: The Brighton Speed Trials, in full The Brighton National Speed Trials, is commonly held to be the oldest running motor race. The first race was held 19–22 July 1905 after Sir Harry Preston persuaded Brighton town council to tarmac the surface of the road adjacent to the beach between the Palace Pier and Black Rock to hold motor racing events. This stretch was renamed Madeira Drive in 1909 and the event is still held there, normally on the second Saturday of September each year. In 1936 "Motor Sport" described the event as: "undoubtedly the most important speed-trials on the British Calendar."
Document 5: 1972 Rothmans International Tennis Tournament: The 1972 Rothmans International Tennis Tournament was a men's professional tennis tournament held on indoor carpet courts in the Royal Albert Hall in London, England. It was the third edition of the tournament and was held from 18–22 January 1972. It was a non-tour event, i.e. not part of either the 1972 Grand Prix or 1972 World Championship Tennis circuit. Cliff Richey won the singles title and $6,960 in prize money after defeating Clark Graebner in a three-hour-and-six-minute final.
Document 6: 1971 BRDC International Trophy: The 23rd BRDC International Trophy meeting - formally the GEN/Daily Express BRDC International Trophy - was held on 8 May 1971 at the Silverstone Circuit, England. The race was run to Formula One and Formula 5000 regulations, and was held over two heats of 26 laps each, the final results being an aggregate of the two. Graham Hill emerged the winner in the unique Brabham BT34 "lobster-claw" car, designed by Ron Tauranac. It would be the two-time World Champion's last victory in a Formula One race. The 1971 event was also notable as one of the few competitive outings for the Lotus 56 gas turbine car. However, suspension failure on only the third lap of the first heat resulted in early retirement for driver Emerson Fittipaldi, although the car held together for long enough to take third place in the second heat.
Document 7: 2017 British Grand Prix: The 2017 British Grand Prix (formally known as the 2017 Formula 1 Rolex British Grand Prix) was a Formula One motor race that took place on 16 July 2017 at the Silverstone Circuit in Silverstone, United Kingdom. This race was the seventy-second running of the British Grand Prix—the first having been held in 1926—and the tenth round of the 2017 Formula One season. The race marked the fifty-second time that the race has been held at the Silverstone Circuit since the Formula One series inception in .
Document 8: Motorsport in the United Kingdom: Motorsport is a popular sport in the United Kingdom. The United Kingdom is a key player in the world of motorsport, hosting rounds of the Formula One World Championship, World Rally Championship and Grand Prix motorcycle racing, amongst others. It is also the home of many of the current teams in Formula One, such as McLaren and Williams, while teams such as Red Bull Racing, Mercedes and Lotus are also based in England. There are also a range of popular national series held such as the British Touring Car Championship. The Motor Sports Association is the official governing body of motorsport in the United Kingdom.
Document 9: 1987 British Grand Prix: The 1987 British Grand Prix (formally the XL Shell Oils British Grand Prix) was a Formula One motor race held on 12 July 1987 at the Silverstone Circuit, Silverstone. It was the seventh race of the 1987 Formula One season. It was the 42nd British Grand Prix and the 23rd to be held at Silverstone. The race was held over 65 laps of the five kilometre circuit for race distance of 311 kilometres.
Document 10: 2016 British Grand Prix: The 2016 British Grand Prix (formally known as the 2016 Formula 1 British Grand Prix) was a Formula One motor race that was held on 10 July 2016 at the Silverstone Circuit in Silverstone, United Kingdom. This race was the seventy-first running of the British Grand Prix, the first having been held in 1926, and was the tenth round of the 2016 Formula One season and the fifty-second time that the race was held at the Silverstone Circuit since the Formula One series inception in .
Document 11: 1971 Race of Champions: The 6th Race of Champions was a non-Championship motor race, run to Formula One rules, held on 21 March 1971 at Brands Hatch circuit in Kent, UK. The race was run over 50 laps of the circuit, and was won by Clay Regazzoni in a Ferrari 312B2.
Document 12: Rothmans 50,000: The Rothmans 50,000 was a motor race held at the Brands Hatch circuit on 28 August 1972 with a prize fund of £50,000.
Document 13: Brands Hatch: Brands Hatch is a motor racing circuit in West Kingsdown in Kent, England. First used as a grasstrack motorcycle circuit on farmland, it hosted 12 runnings of the British Grand Prix between 1964 and 1986 and currently hosts many British and International racing events.
Document 14: 1950 BRDC International Trophy: The 2nd BRDC International Trophy meeting – formally the Daily Express BRDC International Trophy – was held on 26 August 1950 at the Silverstone Circuit, England. The race was run to Formula One regulations, and was held over two heats of 15 laps each, followed by a final race of 35 laps. Italian driver Nino Farina emerged the winner, in an Alfa Romeo 158, repeating his victory from the 1950 British Grand Prix, held at the same circuit in May. He beat his Argentine team-mate Juan Manuel Fangio, and British driver Peter Whitehead in a Ferrari. Other notable entrants were the two BRM V16 cars entered for Raymond Sommer, Peter Walker, Raymond Mays and Reg Parnell. Unfortunately, their legendary lack of reliability resulted in neither car completing a lap in anger.
Document 15: 1973 Rothmans International Tennis Tournament: The 1973 Rothmans International Tennis Tournament was a men's professional tennis tournament held on indoor carpet courts in the Royal Albert Hall in London, England. It was the third edition of the tournament and was held from 18-27 January 1973. The event was part of the 1973 World Championship Tennis circuit. Brian Fairlie won the singles title.
ground_truth: 12