i	j	y
1	1	19.0
1	2	18.6
1	3	20.1
1	4	19.6
2	1	17.8
2	2	18.5
2	3	21.0
2	4	17.9
3	1	19.3
3	2	17.9
3	3	19.5
4	1	20.3
4	2	22.1
5	1	18.8
5	2	17.9
5	3	20.1
5	4	18.6