# read 2 
1   10.0
2   20.0
3   30.0
4   40.0 
5   50.0
6   60.0
7   70.0
8   80.0
9   90.0
10 100.0
9   90.0
8   80.0
7   70.0
6   60.0
5   50.0
4   40.0
3   30.0
2   20.0
1   10.0