Question: Which significant Sinn Féin politician attended the Dr. McKenna Cup?

Context paragraphs:
Eighneachán Ó hAnnluain: Éighneachán (also Éineachán) Ó hAnnluain (1933 — 14 December 1994) was an Irish Sinn Féin politician.  He was elected as a Sinn Féin Teachta Dála (TD) at the 1957 general election for the Monaghan constituency.  He was one of four Sinn Féin TDs elected in that election, the others being Ruairí Ó Brádaigh, John Joe McGirl and John Joe Rice.  None of the four took their seats as Sinn Féin ran on an abstentionist ticket.

Martin McGuinness: James Martin Pacelli McGuinness (Irish: "Séamus Máirtín Pacelli Mag Aonghusa" ; 23 May 1950 – 21 March 2017) was an Irish republican and Sinn Féin politician who was the deputy First Minister of Northern Ireland from May 2007 to January 2017.

2017 Dr. McKenna Cup: The 2017 Dr. McKenna Cup, known for sponsorship reasons as the Bank of Ireland Dr. McKenna Cup, was a Gaelic football competition in the province of Ulster for county and university teams.

Sinn Féin Funds case: The Sinn Féin Funds case ("Buckley and Others v. the Attorney-General and Another") was a 1942–48 Irish court case in which the Sinn Féin party claimed ownership of funds deposited with the High Court in 1924 which had belonged to the Sinn Féin party before 1923.  The Sinn Féin Funds Act 1947, which attempted to halt the court case and assign the funds to Bord Cistí Sinn Féin, was ruled unconstitutional by the Supreme Court in an important judgement on separation of powers and private property rights.  The original action was subsequently decided against Sinn Féin, on the basis that the pre-1923 party was separate from the 1940s party.  Most of the disputed funds were consumed by legal costs.

Republican News: Republican News was a longstanding newspaper/magazine published by Sinn Féin.  Following the split in physical force Irish republicanism in the late 1960s between the "Officials" (Official Sinn Féin — also known as Sinn Féin Gardiner Place — and the Official IRA) and the "Provisionals" (Provisional Sinn Féin — also known as Sinn Féin Kevin Street and now most commonly simply as Sinn Féin — and the Provisional IRA) "Republican News" was eclipsed by "An Phoblacht", a new magazine launched by Provisional Sinn Féin in 1970.  "An Phoblacht" came first and then in early 1970, Joe Graham and Proinsias Mac Airt put together "The Republican News" and it functioned independently for quite a while.  Graham worked on only three issues of it before starting "The Vindicator".  The magazines merged under the name "An Phoblacht/Republican News" in 1979.

Samuel O'Flaherty: Samuel O'Flaherty (died 22 May 1930) was an Irish Sinn Féin politician.  He first stood for election at the 1918 general election as a Sinn Féin candidate for the Donegal East constituency but was defeated by Edward Kelly of the Irish Parliamentary Party.  He was elected unopposed as a Sinn Féin Teachta Dála (TD) to the 2nd Dáil at the 1921 elections for the Donegal constituency.  He opposed the Anglo-Irish Treaty and voted against it.  He was re-elected unopposed as an anti-Treaty Sinn Féin TD at the 1922 general election but did not take his seat.  He lost his seat at the 1923 general election.

2012 Dr. McKenna Cup: The 2012 Dr. McKenna Cup was a Gaelic football competition played under the auspices of Ulster GAA.  The tournament was won by Tyrone, their first McKenna title since 2007.  They defeated Derry in the final.  The final was noted for the attendance of Northern Ireland First Minister Peter Robinson and Deputy First Minister Martin McGuinness.

2016 Dr. McKenna Cup: The 2016 Dr. McKenna Cup, known for sponsorship reasons as the Bank of Ireland Dr. McKenna Cup, was an inter-county and university gaelic football competition in the province of Ulster.

2015 Dr. McKenna Cup: The 2015 Dr. McKenna Cup, known for sponsorship reasons as the Bank of Ireland Dr. McKenna Cup, was an inter-county and colleges hurling competition in the province of Ulster.  As well as the nine county teams, three colleges' teams competed: St Mary's University College, Belfast, Queen's University Belfast and Ulster University.  The final was broadcast live on BBC Sport NI.

John Joe Rice: John Joe Rice (died 1 July 1970) was an Irish Sinn Féin politician.  He was elected as a Sinn Féin Teachta Dála (TD) for the Kerry South constituency at the 1957 general election.  He did not take his seat in the Dáil as Sinn Féin ran on an abstentionist ticket.  He was one of four Sinn Féin TDs elected at the 1957 general election, the others were Ruairí Ó Brádaigh, John Joe McGirl and Eighneachán Ó hAnnluain.  He was defeated at the 1961 general election.

Supporting paragraphs: 2012 Dr. McKenna Cup Martin McGuinness
Answer: Martin McGuinness