Question: What is the name of that retired football manager that used to be a defender for Ajax?

Context paragraphs:
Vladimir Bigorra: Vladimir David Bigorra López (born August 9, 1954) is a retired football defender from Chile, who represented his native country at the 1982 FIFA World Cup, wearing the number four jersey.  He played for several clubs in Chile, including Universidad Católica.  After his active football career Bigorra became a football manager.

Arnaldo Sialle: Arnaldo Adolfo Sialle (born 21 November 1965) is a retired football defender who played in the Argentine Primera División and the Mexican Primera División and a football manager.

Jógvan Martin Olsen: Jógvan Martin Olsen (born 10 July 1961 in Toftir, Faroe Islands) is a retired football player and football manager.  He is the manager of ÍF Fuglafjørður since October 2015.  He was the head coach of the Faroe Islands national football team.

Damjan Ošlaj: Damjan Ošlaj (born 25 August 1976 in SFR Yugoslavia) is a retired football defender and football manager.

Jan Poortvliet: Jan Poortvliet (] ; born 21 September 1955) is a retired football defender from the Netherlands, who represented his native country at the 1978 FIFA World Cup in Argentina, wearing the number two jersey.  His biggest club successes came when he played for PSV Eindhoven in the mid- and late 1970s.  After his retirement in the early 1990s he became a football manager, who worked for clubs like FC Den Bosch, RBC Roosendaal and Stormvogels Telstar.

2008–09 AFC Ajax season: During the 2008–09 season AFC Ajax participated in the Dutch Eredivisie, the KNVB Cup and the UEFA Cup.  The first training took place on Monday July 14, 2008.  The traditional AFC Ajax Open Day was on Tuesday August 5, 2008, followed by a testimonial match for the retired former Ajax defender Jaap Stam.

Kristjan Glibo: Kristjan Glibo (born 1 April 1982 in Bruchsal) is a German football manager and retired football defender or defensive midfielder, who currently is the manager of SV Sandhausen II.

Jaap Stam: Jakob "Jaap" Stam (] ; born 17 July 1972) is a Dutch football manager and former player who is currently the manager of Reading.

Leo van Veen: Leo van Veen (born 6 June 1946 in Utrecht) is a retired football (soccer) player from the Netherlands, who played for FC Utrecht, Los Angeles Aztecs, Ajax Amsterdam and RKC Waalwijk during his career.  Later on he became a football manager.  Van Veen played 555 games in the Eredivisie, scoring 174 goals.

Iván León: Marlon Iván "El Chino" León y León (born 3 March 1967) is a Guatemalan football manager and retired football defender who has played over 10 years for Guatemala's national team.

Supporting paragraphs: 2008–09 AFC Ajax season Jaap Stam
Answer: Jakob "Jaap" Stam