Who plays more singles, Daniel Vacek and Jonathan Erlich?
Daniel Vacek: Daniel Vacek (born 1 April 1971) is a former tennis player from Czechoslovakia and the Czech Republic who turned professional in 1990. 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. Jonathan Erlich:  He plays doubles, primarily.
i don't know