<qa>  How many attempts will the subject self-administer within 30 min after the Screening BaseReversibility FEV1 Test will be performed at the Screening Visit. Within 30 min after the Screening Baseline FEV1 is obtained, the subject will self-administer 180 to 360 mcg Ventolin-HFA 2-4 inhalations. To qualify for the study, the subject needs to demonstrate an FEV1 reversibility of greater than or equal to 12.0, from the same-day Screening Baseline FEV1, with 3 to 8 attempts, at 30 min after inhaling Ventolin-HFA. Reversibility is defined as: 