Premise: Wladimir Klitschko . Overall , he became the second-longest reigning heavyweight champion of all time , and has the second-most successful title defenses total of any heavyweight boxer with 23 ( including his initial reign as WBO champion ) , behind Joe Louis ( 25 ) and ahead of Larry Holmes ( 20 ) and Muhammad Ali ( 19 ) . Klitschko has fought in 29 heavyweight title fights , more than any heavyweight champion in the sport 's history .
Hypothesis: Wladimir Klitschko has fought in 19 heavyweight title fights.
Label: ENTAILMENT