Premise: The Grand Slam tournaments , also called majors , are the four most-important annual tennis events . Steffi Graf . Graf won 22 Grand Slam singles titles . Furthermore , she is the only tennis player to have won each Grand Slam event at least four times . In March 2012 , Tennis Channel picked Graf as the greatest female tennis player ever in their list of 100 greatest tennis players of all time .
Hypothesis: Steffi Graf is an athlete.
Label: ENTAILMENT