group	pre	post
1	18	24
1	18	25
1	21	33
1	18	29
1	18	33
1	20	36
1	23	34
1	23	36
1	21	34
1	17	27
2	18	29
2	24	29
2	20	24
2	18	26
2	24	38
2	22	27
2	15	22
2	19	31