17
1 down/ 2 up/ 3 down 4~5 up / 6~7 down / 8 up / 9 down / 10 up/ 11 down
6 ~7 down 8 up/ 9 down/ 10 up/ 11 down/ 12 up
18 1 down/ 2 up/ 3 down/ 4 up/ 5~6 down/ 7 up/ 8~9 down 10 up/ 11 down/ 12 up
19 1 down/ 2 up/ 3 down
