16:00
0
student
16:00 
28:00
0
12:00
0
36:00
0
20:00
0
11:00
0
12:00
0
13:00
0
29:00
0
29:00
0
25:00
0
24:00
0
12:00
0
11:00
3
12:00
0
12:00
0
31:00
2
30:00
0
22:00
0
22:00
1