seq	row	col	mass n
------------------------------------------------------------------------
1	1	23
1	3001	3
2	2	23
2	3001	3
3	1	2
3	3001	3
4	2	2
4	3001	3
5	3	2
5	3001	3
6	4	2
6	3001	3
7	5	2
7	3001	3
8	6	2
8	3001	3
9	7	2
9	3001	3
10	8	2
10	3001	3