elementary row operation

14:12

1:27:49

1:19:38

2:00:29

1:14:56

19:01

22:19

5:55

11:00

12:32

6:30

18:03

21:55

7:23

15:18

17:22

14:07

11:50

10:30

3:48

23:08

18:36

15:29

2:28

6:51

7:06

14:01

4:15

4:10

3:04

3:59

20:51

18:54

9:22

6:59

4:31

58:35

31:35

37:31

6:13