Question: Who plays more singles, Daniel Vacek and Jonathan Erlich?

Context paragraphs:
2009 Australian Open – Men's Doubles: Jonathan Erlich and Andy Ram were the defending champions, but Erlich chose not to participate due to an elbow injury, and only Ram competed that year.Ram partnered with Max Mirnyi, but lost to Feliciano López and Fernando Verdasco in the second round.

Daniel Vacek: Daniel Vacek (born 1 April 1971) is a former tennis player from Czechoslovakia and the Czech Republic who turned professional in 1990.  He reached the quarterfinals of the 1995 Paris Masters, the 1998 Canada Masters and the 1998 Cincinnati Masters, and achieved a career-high singles ranking of World No. 26 in January 1996.

1993 Volvo International – Doubles: The 1993 Volvo International was a tennis tournament played on outdoor hard courts at the Cullman-Heyman Tennis Center in New Haven, Connecticut, United States and was part of the Championship Series of the 1993 ATP Tour.  The tournament ran from August 16 through August 23, 1993.  Kelly Jones and Rick Leach were the defending champions but only Jones competed that year with Paul Annacone.  Annacone and Jones lost in the semifinals to Cyril Suk and Daniel Vacek.  Suk and Vacek won in the final 7–5, 6–4 against Steve DeVries and David Macpherson.

1996 Italian Open – Men's Doubles: Cyril Suk and Daniel Vacek were the defending champions but they competed with different partners that year, Suk with Hendrik Jan Davids and Vacek with Richey Reneberg.

1995 Kremlin Cup – Singles: Alexander Volkov was the defending champion, but lost to Daniel Vacek in the quarterfinal. Carl-Uwe Steeb won in the final 7–6, 3–6, 7–6 against Daniel Vacek.

1995 Open 13 – Doubles: Jan Siemerink and Daniel Vacek were the defending champions, but did not play together this year.  Siemerink partnered Martin Damm, losing in the quarterfinals.  Vacek partnered Alexander Mronz, losing in the first round.

2000 Heineken Open – Doubles: Jeff Tarango and Daniel Vacek were the defending champions, but Vacek did not participate this year.  Tarango partnered Olivier Delaître, losing in the final.

1996 Davidoff Swiss Indoors – Doubles: Cyril Suk and Daniel Vacek were the defending champions but they competed with different partners that year, Suk with Petr Korda and Vacek with Yevgeny Kafelnikov.

Jonathan Erlich: Jonathan Dario "Yoni" Erlich (Hebrew: יונתן דאריו "יוני" ארליך‎ ‎ , born in Buenos Aires, Argentina, April 5, 1977) is a professional Israeli tennis player.  He plays doubles, primarily.

2011 Aegon Championships – Doubles: Novak Djokovic and Jonathan Erlich were the defending champions, but Djokovic decided not to compete, and Erlich chose to play at Halle instead.

Supporting paragraphs: Daniel Vacek Jonathan Erlich
Answer: Daniel Vacek