算法分析的题
Description A chess rook can move horizontally or vertically to any square in the same row or in the same column of a chessboard.
Find the number of shortest paths by which a rook can move from one corner of a chessboard to the diagonally opposite corner。
Input
a interger number n is row and column of chessboard. 0 < n <=16
Output
the number of shortest paths.
Sample Input
3
or
4
Sample Output
6
or
20
