英语翻译InputThere are multiple test cases.The first line contai

英语翻译
Input
There are multiple test cases.The first line contains an integer n (0 < n ≤ 100).The body of Xiaoxingxing can be decribed as a polygon of n points.Each of the following n lines contains two integers xi and yi (|xi| ≤ 10000,0 ≤ yi ≤ 10000) ,descibing a point of the polygon clockwise or counter-clockwise.The first point of the polygon is always the origin an d the polygon will not be self-crossed.The last line of each test case contains two integers X and Y (xi < X ≤ 10000,0 ≤ Y ≤ 10000),descrbing the position of the Lost Piece.Xiaoxingxing can only roll with some point fixed on the ground where y = 0.
Output
For each test case,first output one line containing "Case x:" where x is the case number (starting from 1).If it is possible for Xiaoxingxing to reach his LP,output the minimum angel in degrees he has to roll before he can reach his LP.The result should be accurate up to 2 decimal places.Otherwise,output "Impossible" instead.
补充一句:谢绝机译！