A defendant who violated the terms of his Proposition 36 probation three times was ineligible for further probation even where only one of his probation violations was drug-related. Further, under People v. Arnold (2004) 33 Cal.4th 294 and People v. Jeffrey (2004) 33 Cal.4th 312, his waiver of presentence custody credits for time spent in residential drug treatment was valid and enforceable.