这题怎么做？
Description：
Inspired by a "Little Bishops" problem, Petya now wants to solve problem for rooks.
A rook is a piece used in the game of chess which is played on a board of square grids. A rook can only move horizontally and vertically from its current position and two rooks attack each other if one is on the path of the other.
Given two numbers n and k, your job is to determine the number of ways one can put k rooks on an n × n chessboard so that no two of them are in attacking positions.
Input：
The input contains several test cases. Each case contains two integers n (1 ≤ n ≤ 12) and k (0 ≤ k ≤ n2）。
Output ：
The input is terminated with n=0 and k=0.
For each case, print a line containing the total number of ways one can put the given number of rooks on a chessboard of the given size so that no two of them are in attacking positions.
Sample Input：
4 4
0 0
Sample Output：
24
要用C语言
