B

Spanning Subtrees

Input: Standard Input

Output: Standard Output

 

Let Kn denote the complete undirected graph with n vertices where n is an even number. In other words, Kn is a graph with n vertices where every two vertices are connected. Your task is to find the maximum number of spanning trees of Kn that can be formed in such a way that no two of these spanning trees have a common edge.

 

Input

Each test case will have an even integer n (2 ≤ n ≤ 400), the number of vertices. The last test case will be followed by a single 0 denoting end of input.

 

Output

For each test case, print a line in the format, “Case X: Y”, where X is the case number & Y is the maximum possible number of spanning trees.

 

Sample Input                             Output for Sample Input

4

0

Case 1: 2

Problemsetter: Mohammad Mahmudur Rahman

Special Thanks to: Manzurur Rahman Khan