01:45
0
student
01:45 
01:30
0
01:19
4
01:07
0
00:52
3
00:26
1
01:12
1
01:23
0
03:15
0
00:25
0
03:48
0
01:15
0
02:50
0
00:38
0
01:06
0
03:40
0
02:25
0
05:22
0
04:40
0
04:55
0
00:25
0
01:26
16
09:03
21
15:00
37
05:37
21
02:02
64
05:44
50
01:11
169