You have to place N queens on a NxN chessboard in such a way that no queen threatens another one.
The rule is that each row and column of the board contains exactly 1 queen , and each diagonal contains no more than 1 queen.
Your mission is to compute how many possible ways to place N queens on that chessboard.
An integer N which represent the size of chessboard and the number of queens
where 1<=N<=50.
An integer which represent the number of possible distributions of N queens.
There is no need to add '\n' at the end of output