<image>To investigate the average daily exercise time X (in minutes) among middle school students in a certain city, the exercise time is categorized into the following four situations for statistics: ① 0-10 minutes; ② 11-20 minutes; ③ 21-30 minutes; ④ More than 30 minutes. A total of 10,000 middle school students participated in this activity. A flowchart of one of the survey items is shown in the figure. If the frequency of students exercising an average of 0-20 minutes per day is 0.15, then the output result is ___.
