Question: Chris Staley is a member of an association of how many independent schools in the United Kingdom?

Context paragraphs:
University of Bristol admissions controversy: The University of Bristol admissions controversy refers to an historic dispute over the admissions process for the University of Bristol in the United Kingdom which occurred in 2003.  The 2003 incident was caused by concerns over bias in the admissions system that were perceived as favouritism towards state school students after the rejection of some students with strong academic records who attended independent schools.  The University's widening participation policy allowed the awarding of slightly lower offers to promising applicants from schools with lower academic achievement.  Controversy surrounding this policy resulted in a brief boycott of the University by some independent schools and intense media debate about the fairness of the admissions policy as well as praise and criticism of the policy and the boycott from politicians, student leaders and education groups.  The boycott was lifted after two months when the Independent School's Council expressed satisfaction with the fairness of the admissions system.  Two years later a survey of independent schools concluded that: "It is likely that rejections which may have seemed discriminatory to parents and schools have in fact, been due to a large rise in suitably qualified applicants" and independent evidence was compiled suggesting that claims of bias were wildly exaggerated.  The controversy has now been superseded by the reality that all British Universities have active 'widening participation' policies designed to increase University applications from lower-achieving schools which tend, de facto, to be state schools.

Headmasters' and Headmistresses' Conference: The Headmasters' and Headmistresses' Conference (HMC) is an association of the headmasters or headmistresses of 283 independent schools (both boarding schools and day schools) in the United Kingdom, Crown dependencies and the Republic of Ireland.  For 2016/2017 the average day fees at a UK HMC school are £4,639 per term or £13,917 per annum.  For 2016/2017 the average full boarding fees at a UK HMC school are £10,709 per term or £32,127 per annum.

Wisbech Grammar School: Wisbech Grammar School is a co-educational independent school in Wisbech, Cambridgeshire, England, for students aged 11 to 18.  Founded by the Wisbech Guild of the Holy Trinity in 1379, it is one of the oldest schools in the country.  The present headmaster is Chris Staley, a member of the Headmasters' and Headmistresses' Conference.  Entry to the senior school at age 11 is based on a competitive examination.  Pupils are also admitted at later stages, including sixth form.

Virginia Association of Independent Schools: Virginia Association of Independent Schools (VAIS) is a non-profit, voluntary membership association of schools within the state of Virginia.  The VAIS is a member of the National Association of Independent Schools.  Prior to its establishment in Charlottesville, Virginia on April 30, 1973, a small number of independent schools’ headmasters known as “The Baker’s Dozen” met informally, teachers at their independent schools held conferences, and development coordinators hosted their own meetings to discuss commonly held educational issues.  While the Virginia State Department of Education accredits independent and other nonpublic pre-school, elementary and secondary schools via the Virginia Council for Private Education (VCPE), the VAIS is a service organization that promotes educational, ethical and professional excellence.

First Assembly Christian School: First Assembly Christian school (FACS) is a college preparatory school located in the Cordova section of Memphis, Tennessee.  FACS was founded in 1972; programs for kindergarten through Grade 8 began in 1972 and grades 9-12 were added in 1975.  The school is fully accredited by the Southern Association of Colleges and Schools.  First Assembly is also a member of the Association of Christian Schools International, Southern Association of Independent Schools, Tennessee Association of Independent Schools, Memphis Association of Independent Schools, and the College Board.  Though strongly supported by First Assembly of God Church, of the Assemblies of God, the school's website identifies itself as Non-denominational Christian.

Independent school (United Kingdom): In the United Kingdom, independent schools (also private schools) are fee-paying private schools, governed by an elected board of governors and independent of many of the regulations and conditions that apply to state-funded schools.  For example, pupils do not have to follow the National Curriculum.  Many of the older, expensive and more exclusive schools catering for the 13–18 age-range in England and Wales are known as public schools as defined by the Public Schools Act 1868.  The term "public" being derived from the fact that they were open to pupils regardless of where they lived or their religion (while in many other countries a public school is run by the state or municipality.) .  Prep schools, (or preparatory school) educate younger children up to the age of 13 to "prepare" them for entry to the public schools and other independent schools.  Some former grammar schools converted to an independent fee paying model following the 1965 Circular 10/65 which marked the end of their state funding, others converted into comprehensive schools.

The Galloway School: The Galloway School is a private, co-educational day school in Atlanta, Georgia, United States.  It was founded by Elliott Galloway in 1969 designed to offer an academic program for children ages 3 through grade 12.  The school has been accredited by is a member of the National Association of Independent Schools (NAIS), the Southern Association of Independent Schools (SAIS), the Georgia Independent School Association (GISA), the Atlanta Area Association of Independent Schools (AAAIS) and the National Association for College Admission Counseling (NACAC).

New Jersey Association of Independent Schools: The New Jersey Association of Independent Schools (NJAIS) serves independent elementary and secondary schools throughout the state of New Jersey.  The Association consists of 70 member schools with a total enrollment of approximately 26,000 students.  The New Jersey Association of Independent Schools is the representative organization of independent schools throughout the state of New Jersey.  It promotes and supports educational, ethical, and professional excellence in member schools, and works to protect their independence through advocacy at the local, state, and federal levels.

New York State Association of Independent Schools: The New York State Association of Independent Schools (NYSAIS) is an association of 194 independent schools, ranging from nurseries to high schools, in New York State.  Founded in 1947, NYSAIS is the second largest state association of independent schools in the United States.  In 2017 its member schools enrolled approximately 82,000 students.  It was established ""to protect independent schools from obstructive legislation and regulation"".  NYSAIS accredits its member schools, provides professional development, and works with community leaders to support the needs and interests of independent schools throughout the state.  NYSAIS is a member of the National Association of Independent Schools (NAIS) as well the NAIS Commission on Accredition.

Independent Schools Association (UK): The Independent Schools Association (ISA) is an organisation of independent schools in the United Kingdom.  Founded in 1879, it is one of the country's oldest such groups.  It is a constituent association of the Independent Schools Council, and has a membership of around 300 schools.  The association's headquarters are in Saffron Walden, Essex.

Supporting paragraphs: Wisbech Grammar School Headmasters' and Headmistresses' Conference
Answer: 283