group	predays	days
1	0	12
1	10	8
1	5	14
1	6	9
1	10	13
1	0	0
1	12	15
1	13	15
1	6	10
1	19	20
2	14	12
2	16	13
2	5	8
2	12	10
2	0	0
2	8	4
2	12	9
2	5	10
2	19	10
2	14	8
3	0	6
3	10	3
3	11	5
3	15	9
3	6	0
3	12	8
3	9	7
3	13	7
3	0	6
3	8	13