enter size (0 to exit)> 
6-queen(s)
list: (5 3 1 6 4 2 )
 _ _ _ _ _ _
| |o| | | | |
| | | |o| | |
| | | | | |o|
|o| | | | | |
| | |o| | | |
| | | | |o| |

enter size (0 to exit)>