new index	atom name	original index
1	C	1
2	C	2
3	C	6
4	C	3
5	C	5
6	C	4
7	H	7
8	H	8
9	H	9
10	H	10
11	H	17
12	H	18
13	H	11
14	H	12
15	H	15
16	H	16
17	H	13
18	H	14
